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     NAME
          tcsh - C shell with file name completion and command line editing

     SYNOPSIS
          tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
          tcsh -l

     DESCRIPTION
          tcsh is an enhanced but completely compatible version of the Berkeley
          UNIX C shell, csh(1).  It is a command language interpreter usable
          both as an interactive login shell and a shell script command
          processor.  It includes a command-line editor (see The command-line
          editor), programmable word completion (see Completion and listing),
          spelling correction (see Spelling correction), a history mechanism
          (see History substitution), job control (see Jobs) and a C-like
          syntax.  The NEW FEATURES section describes major enhancements of tcsh
          over csh(1).  Throughout this manual, features of tcsh not found in
          most csh(1) implementations (specifically, the 4.4BSD csh) are labeled
          with `(+)', and features which are present in csh(1) but not usually
          documented are labeled with `(u)'.

        Argument list processing
          If the first argument (argument 0) to the shell is `-' then it is a
          login shell.  A login shell can be also specified by invoking the
          shell with the -l flag as the only argument.

          The rest of the flag arguments are interpreted as follows:

          -b  Forces a ``break'' from option processing, causing any further
              shell arguments to be treated as non-option arguments.  The
              remaining arguments will not be interpreted as shell options.
              This may be used to pass options to a shell script without
              confusion or possible subterfuge.  The shell will not run a set-
              user ID script without this option.

          -c  Commands are read from the following argument (which must be
              present, and must be a single argument), stored in the command
              shell variable for reference, and executed.  Any remaining
              arguments are placed in the argv shell variable.

          -d  The shell loads the directory stack from ~/.cshdirs as described
              under Startup and shutdown, whether or not it is a login shell.
              (+)

          -Dname[=value]
              Sets the environment variable name to value. (Domain/OS only) (+)

          -e  The shell exits if any invoked command terminates abnormally or
              yields a non-zero exit status.

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          -f  The shell does not load any resource or startup files, or perform
              any command hashing, and thus starts faster.

          -F  The shell uses fork(2) instead of vfork(2) to spawn processes. (+)

          -i  The shell is interactive and prompts for its top-level input, even
              if it appears to not be a terminal.  Shells are interactive
              without this option if their inputs and outputs are terminals.

          -l  The shell is a login shell.  Applicable only if -l is the only
              flag specified.

          -m  The shell loads ~/.tcshrc even if it does not belong to the
              effective user.  Newer versions of su(1) can pass -m to the shell.
              (+)

          -n  The shell parses commands but does not execute them.  This aids in
              debugging shell scripts.

          -q  The shell accepts SIGQUIT (see Signal handling) and behaves when
              it is used under a debugger.  Job control is disabled. (u)

          -s  Command input is taken from the standard input.

          -t  The shell reads and executes a single line of input.  A `\' may be
              used to escape the newline at the end of this line and continue
              onto another line.

          -v  Sets the verbose shell variable, so that command input is echoed
              after history substitution.

          -x  Sets the echo shell variable, so that commands are echoed
              immediately before execution.

          -V  Sets the verbose shell variable even before executing ~/.tcshrc.

          -X  Is to -x as -V is to -v.

          --help
              Print a help message on the standard output and exit. (+)

          --version
              Print the version/platform/compilation options on the standard
              output and exit.  This information is also contained in the
              version shell variable. (+)

          After processing of flag arguments, if arguments remain but none of
          the -c, -i, -s, or -t options were given, the first argument is taken
          as the name of a file of commands, or ``script'', to be executed.  The
          shell opens this file and saves its name for possible resubstitution
          by `$0'.  Because many systems use either the standard version 6 or

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          version 7 shells whose shell scripts are not compatible with this
          shell, the shell uses such a `standard' shell to execute a script
          whose first character is not a `#', i.e., that does not start with a
          comment.

          Remaining arguments are placed in the argv shell variable.

        Startup and shutdown
          A login shell begins by executing commands from the system files
          /etc/csh.cshrc and /etc/csh.login.  It then executes commands from
          files in the user's home directory: first ~/.tcshrc (+) or, if
          ~/.tcshrc is not found, ~/.cshrc, then ~/.history (or the value of the
          histfile shell variable), then ~/.login, and finally ~/.cshdirs (or
          the value of the dirsfile shell variable) (+).  The shell may read
          /etc/csh.login before instead of after /etc/csh.cshrc, and ~/.login
          before instead of after ~/.tcshrc or ~/.cshrc and ~/.history, if so
          compiled; see the version shell variable. (+)

          Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on
          startup.

          For examples of startup files, please consult
          http://tcshrc.sourceforge.net.

          Commands like stty(1) and tset(1), which need be run only once per
          login, usually go in one's ~/.login file.  Users who need to use the
          same set of files with both csh(1) and tcsh can have only a ~/.cshrc
          which checks for the existence of the tcsh shell variable (q.v.)
          before using tcsh-specific commands, or can have both a ~/.cshrc and a
          ~/.tcshrc which sources (see the builtin command) ~/.cshrc.  The rest
          of this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
          not found, ~/.cshrc'.

          In the normal case, the shell begins reading commands from the
          terminal, prompting with `> '.  (Processing of arguments and the use
          of the shell to process files containing command scripts are described
          later.) The shell repeatedly reads a line of command input, breaks it
          into words, places it on the command history list, parses it and
          executes each command in the line.

          One can log out by typing `^D' on an empty line, `logout' or `login'
          or via the shell's autologout mechanism (see the autologout shell
          variable).  When a login shell terminates it sets the logout shell
          variable to `normal' or `automatic' as appropriate, then executes
          commands from the files /etc/csh.logout and ~/.logout.  The shell may
          drop DTR on logout if so compiled; see the version shell variable.

          The names of the system login and logout files vary from system to
          system for compatibility with different csh(1) variants; see FILES.

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        Editing
          We first describe The command-line editor.  The Completion and listing
          and Spelling correction sections describe two sets of functionality
          that are implemented as editor commands but which deserve their own
          treatment.  Finally, Editor commands lists and describes the editor
          commands specific to the shell and their default bindings.

        The command-line editor (+)
          Command-line input can be edited using key sequences much like those
          used in GNU Emacs or vi(1).  The editor is active only when the edit
          shell variable is set, which it is by default in interactive shells.
          The bindkey builtin can display and change key bindings.  Emacs-style
          key bindings are used by default (unless the shell was compiled
          otherwise; see the version shell variable), but bindkey can change the
          key bindings to vi-style bindings en masse.

          The shell always binds the arrow keys (as defined in the TERMCAP
          environment variable) to

              down    down-history
              up      up-history
              left    backward-char
              right   forward-char

          unless doing so would alter another single-character binding.  One can
          set the arrow key escape sequences to the empty string with settc to
          prevent these bindings.  The ANSI/VT100 sequences for arrow keys are
          always bound.

          Other key bindings are, for the most part, what Emacs and vi(1) users
          would expect and can easily be displayed by bindkey, so there is no
          need to list them here.  Likewise, bindkey can list the editor
          commands with a short description of each.

          Note that editor commands do not have the same notion of a ``word'' as
          does the shell.  The editor delimits words with any non-alphanumeric
          characters not in the shell variable wordchars, while the shell
          recognizes only whitespace and some of the characters with special
          meanings to it, listed under Lexical structure.

        Completion and listing (+)
          The shell is often able to complete words when given a unique
          abbreviation.  Type part of a word (for example `ls /usr/lost') and
          hit the tab key to run the complete-word editor command.  The shell
          completes the filename `/usr/lost' to `/usr/lost+found/', replacing
          the incomplete word with the complete word in the input buffer.  (Note
          the terminal `/'; completion adds a `/' to the end of completed
          directories and a space to the end of other completed words, to speed
          typing and provide a visual indicator of successful completion.  The
          addsuffix shell variable can be unset to prevent this.) If no match is
          found (perhaps `/usr/lost+found' doesn't exist), the terminal bell

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          rings.  If the word is already complete (perhaps there is a
          `/usr/lost' on your system, or perhaps you were thinking too far ahead
          and typed the whole thing) a `/' or space is added to the end if it
          isn't already there.

          Completion works anywhere in the line, not at just the end; completed
          text pushes the rest of the line to the right.  Completion in the
          middle of a word often results in leftover characters to the right of
          the cursor that need to be deleted.

          Commands and variables can be completed in much the same way.  For
          example, typing `em[tab]' would complete `em' to `emacs' if emacs were
          the only command on your system beginning with `em'.  Completion can
          find a command in any directory in path or if given a full pathname.
          Typing `echo $ar[tab]' would complete `$ar' to `$argv' if no other
          variable began with `ar'.

          The shell parses the input buffer to determine whether the word you
          want to complete should be completed as a filename, command or
          variable.  The first word in the buffer and the first word following
          `;', `|', `|&', `&&' or `||' is considered to be a command.  A word
          beginning with `$' is considered to be a variable.  Anything else is a
          filename.  An empty line is `completed' as a filename.

          You can list the possible completions of a word at any time by typing
          `^D' to run the delete-char-or-list-or-eof editor command.  The shell
          lists the possible completions using the ls-F builtin (q.v.) and
          reprints the prompt and unfinished command line, for example:

              > ls /usr/l[^D]
              lbin/       lib/        local/      lost+found/
              > ls /usr/l

          If the autolist shell variable is set, the shell lists the remaining
          choices (if any) whenever completion fails:

              > set autolist
              > nm /usr/lib/libt[tab]
              libtermcap.a@ libtermlib.a@
              > nm /usr/lib/libterm

          If autolist is set to `ambiguous', choices are listed only when
          completion fails and adds no new characters to the word being
          completed.

          A filename to be completed can contain variables, your own or others'
          home directories abbreviated with `~' (see Filename substitution) and
          directory stack entries abbreviated with `=' (see Directory stack
          substitution).  For example,

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              > ls ~k[^D]
              kahn    kas     kellogg
              > ls ~ke[tab]
              > ls ~kellogg/

          or

              > set local = /usr/local
              > ls $lo[tab]
              > ls $local/[^D]
              bin/ etc/ lib/ man/ src/
              > ls $local/

          Note that variables can also be expanded explicitly with the expand-
          variables editor command.

          delete-char-or-list-or-eof lists at only the end of the line; in the
          middle of a line it deletes the character under the cursor and on an
          empty line it logs one out or, if ignoreeof is set, does nothing.
          `M-^D', bound to the editor command list-choices, lists completion
          possibilities anywhere on a line, and list-choices (or any one of the
          related editor commands that do or don't delete, list and/or log out,
          listed under delete-char-or-list-or-eof) can be bound to `^D' with the
          bindkey builtin command if so desired.

          The complete-word-fwd and complete-word-back editor commands (not
          bound to any keys by default) can be used to cycle up and down through
          the list of possible completions, replacing the current word with the
          next or previous word in the list.

          The shell variable fignore can be set to a list of suffixes to be
          ignored by completion.  Consider the following:

              > ls
              Makefile        condiments.h~   main.o          side.c
              README          main.c          meal            side.o
              condiments.h    main.c~
              > set fignore = (.o \~)
              > emacs ma[^D]
              main.c   main.c~  main.o
              > emacs ma[tab]
              > emacs main.c

          `main.c~' and `main.o' are ignored by completion (but not listing),
          because they end in suffixes in fignore.  Note that a `\' was needed
          in front of `~' to prevent it from being expanded to home as described
          under Filename substitution.  fignore is ignored if only one
          completion is possible.

          If the complete shell variable is set to `enhance', completion 1)
          ignores case and 2) considers periods, hyphens and underscores (`.',

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          `-' and `_') to be word separators and hyphens and underscores to be
          equivalent.  If you had the following files

              comp.lang.c      comp.lang.perl   comp.std.c++
              comp.lang.c++    comp.std.c

          and typed `mail -f c.l.c[tab]', it would be completed to `mail -f
          comp.lang.c', and ^D would list `comp.lang.c' and `comp.lang.c++'.
          `mail -f c..c++[^D]' would list `comp.lang.c++' and `comp.std.c++'.
          Typing `rm a--file[^D]' in the following directory

              A_silly_file    a-hyphenated-file    another_silly_file

          would list all three files, because case is ignored and hyphens and
          underscores are equivalent.  Periods, however, are not equivalent to
          hyphens or underscores.

          If the complete shell variable is set to `Enhance', completion ignores
          case and differences between a hyphen and an underscore word separator
          only when the user types a lowercase character or a hyphen.  Entering
          an uppercase character or an underscore will not match the
          corresponding lowercase character or hyphen word separator. Typing `rm
          a--file[^D]' in the directory of the previous example would still list
          all three files, but typing `rm A--file' would match only
          `A_silly_file' and typing `rm a__file[^D]' would match just
          `A_silly_file' and `another_silly_file' because the user explicitly
          used an uppercase or an underscore character.

          Completion and listing are affected by several other shell variables:
          recexact can be set to complete on the shortest possible unique match,
          even if more typing might result in a longer match:

              > ls
              fodder   foo      food     foonly
              > set recexact
              > rm fo[tab]

          just beeps, because `fo' could expand to `fod' or `foo', but if we
          type another `o',

              > rm foo[tab]
              > rm foo

          the completion completes on `foo', even though `food' and `foonly'
          also match.  autoexpand can be set to run the expand-history editor
          command before each completion attempt, autocorrect can be set to
          spelling-correct the word to be completed (see Spelling correction)
          before each completion attempt and correct can be set to complete
          commands automatically after one hits `return'.  matchbeep can be set
          to make completion beep or not beep in a variety of situations, and
          nobeep can be set to never beep at all.  nostat can be set to a list

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          of directories and/or patterns that match directories to prevent the
          completion mechanism from stat(2)ing those directories.  listmax and
          listmaxrows can be set to limit the number of items and rows
          (respectively) that are listed without asking first.
          recognize_only_executables can be set to make the shell list only
          executables when listing commands, but it is quite slow.

          Finally, the complete builtin command can be used to tell the shell
          how to complete words other than filenames, commands and variables.
          Completion and listing do not work on glob-patterns (see Filename
          substitution), but the list-glob and expand-glob editor commands
          perform equivalent functions for glob-patterns.

        Spelling correction (+)
          The shell can sometimes correct the spelling of filenames, commands
          and variable names as well as completing and listing them.

          Individual words can be spelling-corrected with the spell-word editor
          command (usually bound to M-s and M-S) and the entire input buffer
          with spell-line (usually bound to M-$).  The correct shell variable
          can be set to `cmd' to correct the command name or `all' to correct
          the entire line each time return is typed, and autocorrect can be set
          to correct the word to be completed before each completion attempt.

          When spelling correction is invoked in any of these ways and the shell
          thinks that any part of the command line is misspelled, it prompts
          with the corrected line:

              > set correct = cmd
              > lz /usr/bin
              CORRECT>ls /usr/bin (y|n|e|a)?

          One can answer `y' or space to execute the corrected line, `e' to
          leave the uncorrected command in the input buffer, `a' to abort the
          command as if `^C' had been hit, and anything else to execute the
          original line unchanged.

          Spelling correction recognizes user-defined completions (see the
          complete builtin command).  If an input word in a position for which a
          completion is defined resembles a word in the completion list,
          spelling correction registers a misspelling and suggests the latter
          word as a correction.  However, if the input word does not match any
          of the possible completions for that position, spelling correction
          does not register a misspelling.

          Like completion, spelling correction works anywhere in the line,
          pushing the rest of the line to the right and possibly leaving extra
          characters to the right of the cursor.

          Beware: spelling correction is not guaranteed to work the way one
          intends, and is provided mostly as an experimental feature.

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          Suggestions and improvements are welcome.

        Editor commands (+)
          `bindkey' lists key bindings and `bindkey -l' lists and briefly
          describes editor commands.  Only new or especially interesting editor
          commands are described here.  See emacs(1) and vi(1) for descriptions
          of each editor's key bindings.

          The character or characters to which each command is bound by default
          is given in parentheses.  `^character' means a control character and
          `M-character' a meta character, typed as escape-character on terminals
          without a meta key.  Case counts, but commands that are bound to
          letters by default are bound to both lower- and uppercase letters for
          convenience.

          complete-word (tab)
                  Completes a word as described under Completion and listing.

          complete-word-back (not bound)
                  Like complete-word-fwd, but steps up from the end of the list.

          complete-word-fwd (not bound)
                  Replaces the current word with the first word in the list of
                  possible completions.  May be repeated to step down through
                  the list.  At the end of the list, beeps and reverts to the
                  incomplete word.

          complete-word-raw (^X-tab)
                  Like complete-word, but ignores user-defined completions.

          copy-prev-word (M-^_)
                  Copies the previous word in the current line into the input
                  buffer.  See also insert-last-word.

          dabbrev-expand (M-/)
                  Expands the current word to the most recent preceding one for
                  which the current is a leading substring, wrapping around the
                  history list (once) if necessary.  Repeating dabbrev-expand
                  without any intervening typing changes to the next previous
                  word etc., skipping identical matches much like history-
                  search-backward does.

          delete-char (not bound)
                  Deletes the character under the cursor.  See also delete-
                  char-or-list-or-eof.

          delete-char-or-eof (not bound)
                  Does delete-char if there is a character under the cursor or
                  end-of-file on an empty line.  See also delete-char-or-list-
                  or-eof.

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          delete-char-or-list (not bound)
                  Does delete-char if there is a character under the cursor or
                  list-choices at the end of the line.  See also delete-char-
                  or-list-or-eof.

          delete-char-or-list-or-eof (^D)
                  Does delete-char if there is a character under the cursor,
                  list-choices at the end of the line or end-of-file on an empty
                  line.  See also those three commands, each of which does only
                  a single action, and delete-char-or-eof, delete-char-or-list
                  and list-or-eof, each of which does a different two out of the
                  three.

          down-history (down-arrow, ^N)
                  Like up-history, but steps down, stopping at the original
                  input line.

          end-of-file (not bound)
                  Signals an end of file, causing the shell to exit unless the
                  ignoreeof shell variable (q.v.) is set to prevent this.  See
                  also delete-char-or-list-or-eof.

          expand-history (M-space)
                  Expands history substitutions in the current word.  See
                  History substitution.  See also magic-space, toggle-literal-
                  history and the autoexpand shell variable.

          expand-glob (^X-*)
                  Expands the glob-pattern to the left of the cursor.  See
                  Filename substitution.

          expand-line (not bound)
                  Like expand-history, but expands history substitutions in each
                  word in the input buffer.

          expand-variables (^X-$)
                  Expands the variable to the left of the cursor.  See Variable
                  substitution.

          history-search-backward (M-p, M-P)
                  Searches backwards through the history list for a command
                  beginning with the current contents of the input buffer up to
                  the cursor and copies it into the input buffer.  The search
                  string may be a glob-pattern (see Filename substitution)
                  containing `*', `?', `[]' or `{}'.  up-history and down-
                  history will proceed from the appropriate point in the history
                  list.  Emacs mode only.  See also history-search-forward and
                  i-search-back.

          history-search-forward (M-n, M-N)
                  Like history-search-backward, but searches forward.

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          i-search-back (not bound)
                  Searches backward like history-search-backward, copies the
                  first match into the input buffer with the cursor positioned
                  at the end of the pattern, and prompts with `bck: ' and the
                  first match.  Additional characters may be typed to extend the
                  search, i-search-back may be typed to continue searching with
                  the same pattern, wrapping around the history list if
                  necessary, (i-search-back must be bound to a single character
                  for this to work) or one of the following special characters
                  may be typed:

                      ^W      Appends the rest of the word under the cursor to
                              the search pattern.
                      delete (or any character bound to backward-delete-char)
                              Undoes the effect of the last character typed and
                              deletes a character from the search pattern if
                              appropriate.
                      ^G      If the previous search was successful, aborts the
                              entire search.  If not, goes back to the last
                              successful search.
                      escape  Ends the search, leaving the current line in the
                              input buffer.

                  Any other character not bound to self-insert-command
                  terminates the search, leaving the current line in the input
                  buffer, and is then interpreted as normal input.  In
                  particular, a carriage return causes the current line to be
                  executed.  Emacs mode only.  See also i-search-fwd and
                  history-search-backward.

          i-search-fwd (not bound)
                  Like i-search-back, but searches forward.

          insert-last-word (M-_)
                  Inserts the last word of the previous input line (`!$') into
                  the input buffer.  See also copy-prev-word.

          list-choices (M-^D)
                  Lists completion possibilities as described under Completion
                  and listing.  See also delete-char-or-list-or-eof and list-
                  choices-raw.

          list-choices-raw (^X-^D)
                  Like list-choices, but ignores user-defined completions.

          list-glob (^X-g, ^X-G)
                  Lists (via the ls-F builtin) matches to the glob-pattern (see
                  Filename substitution) to the left of the cursor.

          list-or-eof (not bound)
                  Does list-choices or end-of-file on an empty line.  See also

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                  delete-char-or-list-or-eof.

          magic-space (not bound)
                  Expands history substitutions in the current line, like
                  expand-history, and inserts a space.  magic-space is designed
                  to be bound to the space bar, but is not bound by default.

          normalize-command (^X-?)
                  Searches for the current word in PATH and, if it is found,
                  replaces it with the full path to the executable.  Special
                  characters are quoted.  Aliases are expanded and quoted but
                  commands within aliases are not.  This command is useful with
                  commands that take commands as arguments, e.g., `dbx' and `sh
                  -x'.

          normalize-path (^X-n, ^X-N)
                  Expands the current word as described under the `expand'
                  setting of the symlinks shell variable.

          overwrite-mode (unbound)
                  Toggles between input and overwrite modes.

          run-fg-editor (M-^Z)
                  Saves the current input line and looks for a stopped job with
                  a name equal to the last component of the file name part of
                  the EDITOR or VISUAL environment variables, or, if neither is
                  set, `ed' or `vi'.  If such a job is found, it is restarted as
                  if `fg %job' had been typed.  This is used to toggle back and
                  forth between an editor and the shell easily.  Some people
                  bind this command to `^Z' so they can do this even more
                  easily.

          run-help (M-h, M-H)
                  Searches for documentation on the current command, using the
                  same notion of `current command' as the completion routines,
                  and prints it.  There is no way to use a pager; run-help is
                  designed for short help files.  If the special alias
                  helpcommand is defined, it is run with the command name as a
                  sole argument.  Else, documentation should be in a file named
                  command.help, command.1, command.6, command.8 or command,
                  which should be in one of the directories listed in the HPATH
                  environment variable.  If there is more than one help file
                  only the first is printed.

          self-insert-command (text characters)
                  In insert mode (the default), inserts the typed character into
                  the input line after the character under the cursor.  In
                  overwrite mode, replaces the character under the cursor with
                  the typed character.  The input mode is normally preserved
                  between lines, but the inputmode shell variable can be set to
                  `insert' or `overwrite' to put the editor in that mode at the

                                       - 12 -      Formatted:  February 27, 2012

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                                  14 February 2012

                  beginning of each line.  See also overwrite-mode.

          sequence-lead-in (arrow prefix, meta prefix, ^X)
                  Indicates that the following characters are part of a multi-
                  key sequence.  Binding a command to a multi-key sequence
                  really creates two bindings: the first character to sequence-
                  lead-in and the whole sequence to the command.  All sequences
                  beginning with a character bound to sequence-lead-in are
                  effectively bound to undefined-key unless bound to another
                  command.

          spell-line (M-$)
                  Attempts to correct the spelling of each word in the input
                  buffer, like spell-word, but ignores words whose first
                  character is one of `-', `!', `^' or `%', or which contain
                  `\', `*' or `?', to avoid problems with switches,
                  substitutions and the like.  See Spelling correction.

          spell-word (M-s, M-S)
                  Attempts to correct the spelling of the current word as
                  described under Spelling correction.  Checks each component of
                  a word which appears to be a pathname.

          toggle-literal-history (M-r, M-R)
                  Expands or `unexpands' history substitutions in the input
                  buffer.  See also expand-history and the autoexpand shell
                  variable.

          undefined-key (any unbound key)
                  Beeps.

          up-history (up-arrow, ^P)
                  Copies the previous entry in the history list into the input
                  buffer.  If histlit is set, uses the literal form of the
                  entry.  May be repeated to step up through the history list,
                  stopping at the top.

          vi-search-back (?)
                  Prompts with `?' for a search string (which may be a glob-
                  pattern, as with history-search-backward), searches for it and
                  copies it into the input buffer.  The bell rings if no match
                  is found.  Hitting return ends the search and leaves the last
                  match in the input buffer.  Hitting escape ends the search and
                  executes the match.  vi mode only.

          vi-search-fwd (/)
                  Like vi-search-back, but searches forward.

          which-command (M-?)
                  Does a which (see the description of the builtin command) on
                  the first word of the input buffer.

                                       - 13 -      Formatted:  February 27, 2012

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                                  14 February 2012

          yank-pop (M-y)
                  When executed immediately after a yank or another yank-pop,
                  replaces the yanked string with the next previous string from
                  the killring. This also has the effect of rotating the
                  killring, such that this string will be considered the most
                  recently killed by a later yank command. Repeating yank-pop
                  will cycle through the killring any number of times.

        Lexical structure
          The shell splits input lines into words at blanks and tabs.  The
          special characters `&', `|', `;', `<', `>', `(', and `)' and the
          doubled characters `&&', `||', `<<' and `>>' are always separate
          words, whether or not they are surrounded by whitespace.

          When the shell's input is not a terminal, the character `#' is taken
          to begin a comment.  Each `#' and the rest of the input line on which
          it appears is discarded before further parsing.

          A special character (including a blank or tab) may be prevented from
          having its special meaning, and possibly made part of another word, by
          preceding it with a backslash (`\') or enclosing it in single (`''),
          double (`"') or backward (``') quotes.  When not otherwise quoted a
          newline preceded by a `\' is equivalent to a blank, but inside quotes
          this sequence results in a newline.

          Furthermore, all Substitutions (see below) except History substitution
          can be prevented by enclosing the strings (or parts of strings) in
          which they appear with single quotes or by quoting the crucial
          character(s) (e.g., `$' or ``' for Variable substitution or Command
          substitution respectively) with `\'.  (Alias substitution is no
          exception: quoting in any way any character of a word for which an
          alias has been defined prevents substitution of the alias.  The usual
          way of quoting an alias is to precede it with a backslash.) History
          substitution is prevented by backslashes but not by single quotes.
          Strings quoted with double or backward quotes undergo Variable
          substitution and Command substitution, but other substitutions are
          prevented.

          Text inside single or double quotes becomes a single word (or part of
          one).  Metacharacters in these strings, including blanks and tabs, do
          not form separate words.  Only in one special case (see Command
          substitution below) can a double-quoted string yield parts of more
          than one word; single-quoted strings never do.  Backward quotes are
          special: they signal Command substitution (q.v.), which may result in
          more than one word.

          Quoting complex strings, particularly strings which themselves contain
          quoting characters, can be confusing.  Remember that quotes need not
          be used as they are in human writing!  It may be easier to quote not
          an entire string, but only those parts of the string which need
          quoting, using different types of quoting to do so if appropriate.

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                                  14 February 2012

          The backslash_quote shell variable (q.v.) can be set to make
          backslashes always quote `\', `'', and `"'.  (+) This may make complex
          quoting tasks easier, but it can cause syntax errors in csh(1)
          scripts.

        Substitutions
          We now describe the various transformations the shell performs on the
          input in the order in which they occur.  We note in passing the data
          structures involved and the commands and variables which affect them.
          Remember that substitutions can be prevented by quoting as described
          under Lexical structure.

        History substitution
          Each command, or ``event'', input from the terminal is saved in the
          history list.  The previous command is always saved, and the history
          shell variable can be set to a number to save that many commands.  The
          histdup shell variable can be set to not save duplicate events or
          consecutive duplicate events.

          Saved commands are numbered sequentially from 1 and stamped with the
          time.  It is not usually necessary to use event numbers, but the
          current event number can be made part of the prompt by placing an `!'
          in the prompt shell variable.

          The shell actually saves history in expanded and literal (unexpanded)
          forms.  If the histlit shell variable is set, commands that display
          and store history use the literal form.

          The history builtin command can print, store in a file, restore and
          clear the history list at any time, and the savehist and histfile
          shell variables can be set to store the history list automatically on
          logout and restore it on login.

          History substitutions introduce words from the history list into the
          input stream, making it easy to repeat commands, repeat arguments of a
          previous command in the current command, or fix spelling mistakes in
          the previous command with little typing and a high degree of
          confidence.

          History substitutions begin with the character `!'.  They may begin
          anywhere in the input stream, but they do not nest.  The `!' may be
          preceded by a `\' to prevent its special meaning; for convenience, a
          `!' is passed unchanged when it is followed by a blank, tab, newline,
          `=' or `('.  History substitutions also occur when an input line
          begins with `^'.  This special abbreviation will be described later.
          The characters used to signal history substitution (`!' and `^') can
          be changed by setting the histchars shell variable.  Any input line
          which contains a history substitution is printed before it is
          executed.

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                                  14 February 2012

          A history substitution may have an ``event specification'', which
          indicates the event from which words are to be taken, a ``word
          designator'', which selects particular words from the chosen event,
          and/or a ``modifier'', which manipulates the selected words.

          An event specification can be

              n       A number, referring to a particular event
              -n      An offset, referring to the event n before the current
                      event
              #       The current event.  This should be used carefully in
                      csh(1), where there is no check for recursion.  tcsh
                      allows 10 levels of recursion.  (+)
              !       The previous event (equivalent to `-1')
              s       The most recent event whose first word begins with the
                      string s
              ?s?     The most recent event which contains the string s.  The
                      second `?' can be omitted if it is immediately followed by
                      a newline.

          For example, consider this bit of someone's history list:

               9  8:30    nroff -man wumpus.man
              10  8:31    cp wumpus.man wumpus.man.old
              11  8:36    vi wumpus.man
              12  8:37    diff wumpus.man.old wumpus.man

          The commands are shown with their event numbers and time stamps.  The
          current event, which we haven't typed in yet, is event 13.  `!11' and
          `!-2' refer to event 11.  `!!' refers to the previous event, 12.  `!!'
          can be abbreviated `!' if it is followed by `:' (`:' is described
          below).  `!n' refers to event 9, which begins with `n'.  `!?old?' also
          refers to event 12, which contains `old'.  Without word designators or
          modifiers history references simply expand to the entire event, so we
          might type `!cp' to redo the copy command or `!!|more' if the `diff'
          output scrolled off the top of the screen.

          History references may be insulated from the surrounding text with
          braces if necessary.  For example, `!vdoc' would look for a command
          beginning with `vdoc', and, in this example, not find one, but
          `!{v}doc' would expand unambiguously to `vi wumpus.mandoc'.  Even in
          braces, history substitutions do not nest.

          (+) While csh(1) expands, for example, `!3d' to event 3 with the
          letter `d' appended to it, tcsh expands it to the last event beginning
          with `3d'; only completely numeric arguments are treated as event
          numbers.  This makes it possible to recall events beginning with
          numbers.  To expand `!3d' as in csh(1) say `!{3}d'.

          To select words from an event we can follow the event specification by
          a `:' and a designator for the desired words.  The words of an input

                                       - 16 -      Formatted:  February 27, 2012

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                                  14 February 2012

          line are numbered from 0, the first (usually command) word being 0,
          the second word (first argument) being 1, etc.  The basic word
          designators are:

              0       The first (command) word
              n       The nth argument
              ^       The first argument, equivalent to `1'
              $       The last argument
              %       The word matched by an ?s? search
              x-y     A range of words
              -y      Equivalent to `0-y'
              *       Equivalent to `^-$', but returns nothing if the event
                      contains only 1 word
              x*      Equivalent to `x-$'
              x-      Equivalent to `x*', but omitting the last word (`$')

          Selected words are inserted into the command line separated by single
          blanks.  For example, the `diff' command in the previous example might
          have been typed as `diff !!:1.old !!:1' (using `:1' to select the
          first argument from the previous event) or `diff !-2:2 !-2:1' to
          select and swap the arguments from the `cp' command.  If we didn't
          care about the order of the `diff' we might have said `diff !-2:1-2'
          or simply `diff !-2:*'.  The `cp' command might have been written `cp
          wumpus.man !#:1.old', using `#' to refer to the current event.  `!n:-
          hurkle.man' would reuse the first two words from the `nroff' command
          to say `nroff -man hurkle.man'.

          The `:' separating the event specification from the word designator
          can be omitted if the argument selector begins with a `^', `$', `*',
          `%' or `-'.  For example, our `diff' command might have been `diff
          !!^.old !!^' or, equivalently, `diff !!$.old !!$'.  However, if `!!'
          is abbreviated `!', an argument selector beginning with `-' will be
          interpreted as an event specification.

          A history reference may have a word designator but no event
          specification.  It then references the previous command.  Continuing
          our `diff' example, we could have said simply `diff !^.old !^' or, to
          get the arguments in the opposite order, just `diff !*'.

          The word or words in a history reference can be edited, or
          ``modified'', by following it with one or more modifiers, each
          preceded by a `:':

              h       Remove a trailing pathname component, leaving the head.
              t       Remove all leading pathname components, leaving the tail.
              r       Remove a filename extension `.xxx', leaving the root name.
              e       Remove all but the extension.
              u       Uppercase the first lowercase letter.
              l       Lowercase the first uppercase letter.
              s/l/r/  Substitute l for r.  l is simply a string like r, not a
                      regular expression as in the eponymous ed(1) command.  Any

                                       - 17 -      Formatted:  February 27, 2012

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                                  14 February 2012

                      character may be used as the delimiter in place of `/'; a
                      `\' can be used to quote the delimiter inside l and r.
                      The character `&' in the r is replaced by l; `\' also
                      quotes `&'.  If l is empty (``''), the l from a previous
                      substitution or the s from a previous search or event
                      number in event specification is used.  The trailing
                      delimiter may be omitted if it is immediately followed by
                      a newline.
              &       Repeat the previous substitution.
              g       Apply the following modifier once to each word.
              a (+)   Apply the following modifier as many times as possible to
                      a single word.  `a' and `g' can be used together to apply
                      a modifier globally.  With the `s' modifier, only the
                      patterns contained in the original word are substituted,
                      not patterns that contain any substitution result.
              p       Print the new command line but do not execute it.
              q       Quote the substituted words, preventing further
                      substitutions.
              x       Like q, but break into words at blanks, tabs and newlines.

          Modifiers are applied to only the first modifiable word (unless `g' is
          used).  It is an error for no word to be modifiable.

          For example, the `diff' command might have been written as `diff
          wumpus.man.old !#^:r', using `:r' to remove `.old' from the first
          argument on the same line (`!#^').  We could say `echo hello out
          there', then `echo !*:u' to capitalize `hello', `echo !*:au' to say it
          out loud, or `echo !*:agu' to really shout.  We might follow `mail -s
          "I forgot my password" rot' with `!:s/rot/root' to correct the
          spelling of `root' (but see Spelling correction for a different
          approach).

          There is a special abbreviation for substitutions.  `^', when it is
          the first character on an input line, is equivalent to `!:s^'.  Thus
          we might have said `^rot^root' to make the spelling correction in the
          previous example.  This is the only history substitution which does
          not explicitly begin with `!'.

          (+) In csh as such, only one modifier may be applied to each history
          or variable expansion.  In tcsh, more than one may be used, for
          example

              % mv wumpus.man /usr/man/man1/wumpus.1
              % man !$:t:r
              man wumpus

          In csh, the result would be `wumpus.1:r'.  A substitution followed by
          a colon may need to be insulated from it with braces:

              > mv a.out /usr/games/wumpus
              > setenv PATH !$:h:$PATH

                                       - 18 -      Formatted:  February 27, 2012

     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

              Bad ! modifier: $.
              > setenv PATH !{-2$:h}:$PATH
              setenv PATH /usr/games:/bin:/usr/bin:.

          The first attempt would succeed in csh but fails in tcsh, because tcsh
          expects another modifier after the second colon rather than `$'.

          Finally, history can be accessed through the editor as well as through
          the substitutions just described.  The up- and down-history, history-
          search-backward and -forward, i-search-back and -fwd, vi-search-back
          and -fwd, copy-prev-word and insert-last-word editor commands search
          for events in the history list and copy them into the input buffer.
          The toggle-literal-history editor command switches between the
          expanded and literal forms of history lines in the input buffer.
          expand-history and expand-line expand history substitutions in the
          current word and in the entire input buffer respectively.

        Alias substitution
          The shell maintains a list of aliases which can be set, unset and
          printed by the alias and unalias commands.  After a command line is
          parsed into simple commands (see Commands) the first word of each
          command, left-to-right, is checked to see if it has an alias.  If so,
          the first word is replaced by the alias.  If the alias contains a
          history reference, it undergoes History substitution (q.v.) as though
          the original command were the previous input line.  If the alias does
          not contain a history reference, the argument list is left untouched.

          Thus if the alias for `ls' were `ls -l' the command `ls /usr' would
          become `ls -l /usr', the argument list here being undisturbed.  If the
          alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill' would
          become `grep bill /etc/passwd'.  Aliases can be used to introduce
          parser metasyntax.  For example, `alias print 'pr \!* | lpr'' defines
          a ``command'' (`print') which pr(1)s its arguments to the line
          printer.

          Alias substitution is repeated until the first word of the command has
          no alias.  If an alias substitution does not change the first word (as
          in the previous example) it is flagged to prevent a loop.  Other loops
          are detected and cause an error.

          Some aliases are referred to by the shell; see Special aliases.

        Variable substitution
          The shell maintains a list of variables, each of which has as value a
          list of zero or more words.  The values of shell variables can be
          displayed and changed with the set and unset commands.  The system
          maintains its own list of ``environment'' variables.  These can be
          displayed and changed with printenv, setenv and unsetenv.

          (+) Variables may be made read-only with `set -r' (q.v.).  Read-only
          variables may not be modified or unset; attempting to do so will cause

                                       - 19 -      Formatted:  February 27, 2012

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                                  14 February 2012

          an error.  Once made read-only, a variable cannot be made writable, so
          `set -r' should be used with caution.  Environment variables cannot be
          made read-only.

          Some variables are set by the shell or referred to by it.  For
          instance, the argv variable is an image of the shell's argument list,
          and words of this variable's value are referred to in special ways.
          Some of the variables referred to by the shell are toggles; the shell
          does not care what their value is, only whether they are set or not.
          For instance, the verbose variable is a toggle which causes command
          input to be echoed.  The -v command line option sets this variable.
          Special shell variables lists all variables which are referred to by
          the shell.

          Other operations treat variables numerically.  The `@' command permits
          numeric calculations to be performed and the result assigned to a
          variable.  Variable values are, however, always represented as (zero
          or more) strings.  For the purposes of numeric operations, the null
          string is considered to be zero, and the second and subsequent words
          of multi-word values are ignored.

          After the input line is aliased and parsed, and before each command is
          executed, variable substitution is performed keyed by `$' characters.
          This expansion can be prevented by preceding the `$' with a `\' except
          within `"'s where it always occurs, and within `''s where it never
          occurs.  Strings quoted by ``' are interpreted later (see Command
          substitution below) so `$' substitution does not occur there until
          later, if at all.  A `$' is passed unchanged if followed by a blank,
          tab, or end-of-line.

          Input/output redirections are recognized before variable expansion,
          and are variable expanded separately.  Otherwise, the command name and
          entire argument list are expanded together.  It is thus possible for
          the first (command) word (to this point) to generate more than one
          word, the first of which becomes the command name, and the rest of
          which become arguments.

          Unless enclosed in `"' or given the `:q' modifier the results of
          variable substitution may eventually be command and filename
          substituted.  Within `"', a variable whose value consists of multiple
          words expands to a (portion of a) single word, with the words of the
          variable's value separated by blanks.  When the `:q' modifier is
          applied to a substitution the variable will expand to multiple words
          with each word separated by a blank and quoted to prevent later
          command or filename substitution.

          The following metasequences are provided for introducing variable
          values into the shell input.  Except as noted, it is an error to
          reference a variable which is not set.

                                       - 20 -      Formatted:  February 27, 2012

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                                  14 February 2012

          $name
          ${name} Substitutes the words of the value of variable name, each
                  separated by a blank.  Braces insulate name from following
                  characters which would otherwise be part of it.  Shell
                  variables have names consisting of letters and digits starting
                  with a letter.  The underscore character is considered a
                  letter.  If name is not a shell variable, but is set in the
                  environment, then that value is returned (but some of the
                  other forms given below are not available in this case).
          $name[selector]
          ${name[selector]}
                  Substitutes only the selected words from the value of name.
                  The selector is subjected to `$' substitution and may consist
                  of a single number or two numbers separated by a `-'.  The
                  first word of a variable's value is numbered `1'.  If the
                  first number of a range is omitted it defaults to `1'.  If the
                  last member of a range is omitted it defaults to `$#name'.
                  The selector `*' selects all words.  It is not an error for a
                  range to be empty if the second argument is omitted or in
                  range.
          $0      Substitutes the name of the file from which command input is
                  being read.  An error occurs if the name is not known.
          $number
          ${number}
                  Equivalent to `$argv[number]'.
          $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

          The `:' modifiers described under History substitution, except for
          `:p', can be applied to the substitutions above.  More than one may be
          used.  (+) Braces may be needed to insulate a variable substitution
          from a literal colon just as with History substitution (q.v.); any
          modifiers must appear within the braces.

          The following substitutions can not be modified with `:' modifiers.

          $?name
          ${?name}
                  Substitutes the string `1' if name is set, `0' if it is not.
          $?0     Substitutes `1' if the current input filename is known, `0' if
                  it is not.  Always `0' in interactive shells.
          $#name
          ${#name}
                  Substitutes the number of words in name.
          $#      Equivalent to `$#argv'.  (+)
          $%name
          ${%name}
                  Substitutes the number of characters in name.  (+)
          $%number
          ${%number}
                  Substitutes the number of characters in $argv[number].  (+)

                                       - 21 -      Formatted:  February 27, 2012

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                                  14 February 2012

          $?      Equivalent to `$status'.  (+)
          $$      Substitutes the (decimal) process number of the (parent)
                  shell.
          $!      Substitutes the (decimal) process number of the last
                  background process started by this shell.  (+)
          $_      Substitutes the command line of the last command executed.
                  (+)
          $<      Substitutes a line from the standard input, with no further
                  interpretation thereafter.  It can be used to read from the
                  keyboard in a shell script.  (+) While csh always quotes $<,
                  as if it were equivalent to `$<:q', tcsh does not.
                  Furthermore, when tcsh is waiting for a line to be typed the
                  user may type an interrupt to interrupt the sequence into
                  which the line is to be substituted, but csh does not allow
                  this.

          The editor command expand-variables, normally bound to `^X-$', can be
          used to interactively expand individual variables.

        Command, filename and directory stack substitution
          The remaining substitutions are applied selectively to the arguments
          of builtin commands.  This means that portions of expressions which
          are not evaluated are not subjected to these expansions.  For commands
          which are not internal to the shell, the command name is substituted
          separately from the argument list.  This occurs very late, after
          input-output redirection is performed, and in a child of the main
          shell.

        Command substitution
          Command substitution is indicated by a command enclosed in ``'.  The
          output from such a command is broken into separate words at blanks,
          tabs and newlines, and null words are discarded.  The output is
          variable and command substituted and put in place of the original
          string.

          Command substitutions inside double quotes (`"') retain blanks and
          tabs; only newlines force new words.  The single final newline does
          not force a new word in any case.  It is thus possible for a command
          substitution to yield only part of a word, even if the command outputs
          a complete line.

          By default, the shell since version 6.12 replaces all newline and
          carriage return characters in the command by spaces.  If this is
          switched off by unsetting csubstnonl, newlines separate commands as
          usual.

        Filename substitution
          If a word contains any of the characters `*', `?', `[' or `{' or
          begins with the character `~' it is a candidate for filename
          substitution, also known as ``globbing''.  This word is then regarded
          as a pattern (``glob-pattern''), and replaced with an alphabetically

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                                  14 February 2012

          sorted list of file names which match the pattern.

          In matching filenames, the character `.' at the beginning of a
          filename or immediately following a `/', as well as the character `/'
          must be matched explicitly (unless either globdot or globstar or both
          are set(+)).  The character `*' matches any string of characters,
          including the null string.  The character `?' matches any single
          character. The sequence `[...]' matches any one of the characters
          enclosed. Within `[...]', a pair of characters separated by `-'
          matches any character lexically between the two.

          (+) Some glob-patterns can be negated: The sequence `[^...]' matches
          any single character not specified by the characters and/or ranges of
          characters in the braces.

          An entire glob-pattern can also be negated with `^':

              > echo *
              bang crash crunch ouch
              > echo ^cr*
              bang ouch

          Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or
          `~' (below) are not negated correctly.

          The metanotation `a{b,c,d}e' is a shorthand for `abe ace ade'.  Left-
          to-right order is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
          `/usr/source/s1/oldls.c /usr/source/s1/ls.c'.  The results of matches
          are sorted separately at a low level to preserve this order:
          `../{memo,*box}' might expand to `../memo ../box ../mbox'.  (Note that
          `memo' was not sorted with the results of matching `*box'.) It is not
          an error when this construct expands to files which do not exist, but
          it is possible to get an error from a command to which the expanded
          list is passed.  This construct may be nested.  As a special case the
          words `{', `}' and `{}' are passed undisturbed.

          The character `~' at the beginning of a filename refers to home
          directories.  Standing alone, i.e., `~', it expands to the invoker's
          home directory as reflected in the value of the home shell variable.
          When followed by a name consisting of letters, digits and `-'
          characters the shell searches for a user with that name and
          substitutes their home directory; thus `~ken' might expand to
          `/usr/ken' and `~ken/chmach' to `/usr/ken/chmach'.  If the character
          `~' is followed by a character other than a letter or `/' or appears
          elsewhere than at the beginning of a word, it is left undisturbed.  A
          command like `setenv MANPATH /usr/man:/usr/local/man:~/lib/man' does
          not, therefore, do home directory substitution as one might hope.

          It is an error for a glob-pattern containing `*', `?', `[' or `~',
          with or without `^', not to match any files.  However, only one
          pattern in a list of glob-patterns must match a file (so that, e.g.,

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                                  14 February 2012

          `rm *.a *.c *.o' would fail only if there were no files in the current
          directory ending in `.a', `.c', or `.o'), and if the nonomatch shell
          variable is set a pattern (or list of patterns) which matches nothing
          is left unchanged rather than causing an error.

          The globstar shell variable can be set to allow `**' or `***' as a
          file glob pattern that matches any string of characters including `/',
          recursively traversing any existing sub-directories.  For example, `ls
          **.c' will list all the .c files in the current directory tree.  If
          used by itself, it will match match zero or more sub-directories (e.g.
          `ls /usr/include/**/time.h' will list any file named `time.h' in the
          /usr/include directory tree; `ls /usr/include/**time.h' will match any
          file in the /usr/include directory tree ending in `time.h'; and `ls
          /usr/include/**time**.h' will match any .h file with `time' either in
          a subdirectory name or in the filename itself).  To prevent problems
          with recursion, the `**' glob-pattern will not descend into a symbolic
          link containing a directory.  To override this, use `***' (+)

          The noglob shell variable can be set to prevent filename substitution,
          and the expand-glob editor command, normally bound to `^X-*', can be
          used to interactively expand individual filename substitutions.

        Directory stack substitution (+)
          The directory stack is a list of directories, numbered from zero, used
          by the pushd, popd and dirs builtin commands (q.v.).  dirs can print,
          store in a file, restore and clear the directory stack at any time,
          and the savedirs and dirsfile shell variables can be set to store the
          directory stack automatically on logout and restore it on login.  The
          dirstack shell variable can be examined to see the directory stack and
          set to put arbitrary directories into the directory stack.

          The character `=' followed by one or more digits expands to an entry
          in the directory stack.  The special case `=-' expands to the last
          directory in the stack.  For example,

              > dirs -v
              0       /usr/bin
              1       /usr/spool/uucp
              2       /usr/accts/sys
              > echo =1
              /usr/spool/uucp
              > echo =0/calendar
              /usr/bin/calendar
              > echo =-
              /usr/accts/sys

          The noglob and nonomatch shell variables and the expand-glob editor
          command apply to directory stack as well as filename substitutions.

        Other substitutions (+)
          There are several more transformations involving filenames, not

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                                  14 February 2012

          strictly related to the above but mentioned here for completeness.
          Any filename may be expanded to a full path when the symlinks variable
          (q.v.) is set to `expand'.  Quoting prevents this expansion, and the
          normalize-path editor command does it on demand.  The normalize-
          command editor command expands commands in PATH into full paths on
          demand.  Finally, cd and pushd interpret `-' as the old working
          directory (equivalent to the shell variable owd).  This is not a
          substitution at all, but an abbreviation recognized by only those
          commands.  Nonetheless, it too can be prevented by quoting.

        Commands
          The next three sections describe how the shell executes commands and
          deals with their input and output.

        Simple commands, pipelines and sequences
          A simple command is a sequence of words, the first of which specifies
          the command to be executed.  A series of simple commands joined by `|'
          characters forms a pipeline.  The output of each command in a pipeline
          is connected to the input of the next.

          Simple commands and pipelines may be joined into sequences with `;',
          and will be executed sequentially.  Commands and pipelines can also be
          joined into sequences with `||' or `&&', indicating, as in the C
          language, that the second is to be executed only if the first fails or
          succeeds respectively.

          A simple command, pipeline or sequence may be placed in parentheses,
          `()', to form a simple command, which may in turn be a component of a
          pipeline or sequence.  A command, pipeline or sequence can be executed
          without waiting for it to terminate by following it with an `&'.

        Builtin and non-builtin command execution
          Builtin commands are executed within the shell.  If any component of a
          pipeline except the last is a builtin command, the pipeline is
          executed in a subshell.

          Parenthesized commands are always executed in a subshell.

              (cd; pwd); pwd

          thus prints the home directory, leaving you where you were (printing
          this after the home directory), while

              cd; pwd

          leaves you in the home directory.  Parenthesized commands are most
          often used to prevent cd from affecting the current shell.

          When a command to be executed is found not to be a builtin command the
          shell attempts to execute the command via execve(2).  Each word in the
          variable path names a directory in which the shell will look for the

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                                  14 February 2012

          command.  If the shell is not given a -f option, the shell hashes the
          names in these directories into an internal table so that it will try
          an execve(2) in only a directory where there is a possibility that the
          command resides there.  This greatly speeds command location when a
          large number of directories are present in the search path. This
          hashing mechanism is not used:

          1.  If hashing is turned explicitly off via unhash.

          2.  If the shell was given a -f argument.

          3.  For each directory component of path which does not begin with a
              `/'.

          4.  If the command contains a `/'.

          In the above four cases the shell concatenates each component of the
          path vector with the given command name to form a path name of a file
          which it then attempts to execute it. If execution is successful, the
          search stops.

          If the file has execute permissions but is not an executable to the
          system (i.e., it is neither an executable binary nor a script that
          specifies its interpreter), then it is assumed to be a file containing
          shell commands and a new shell is spawned to read it.  The shell
          special alias may be set to specify an interpreter other than the
          shell itself.

          On systems which do not understand the `#!' script interpreter
          convention the shell may be compiled to emulate it; see the version
          shell variable.  If so, the shell checks the first line of the file to
          see if it is of the form `#!interpreter arg ...'.  If it is, the shell
          starts interpreter with the given args and feeds the file to it on
          standard input.

        Input/output
          The standard input and standard output of a command may be redirected
          with the following syntax:

          < name  Open file name (which is first variable, command and filename
                  expanded) as the standard input.
          << word Read the shell input up to a line which is identical to word.
                  word is not subjected to variable, filename or command
                  substitution, and each input line is compared to word before
                  any substitutions are done on this input line.  Unless a
                  quoting `\', `"', `' or ``' appears in word variable and
                  command substitution is performed on the intervening lines,
                  allowing `\' to quote `$', `\' and ``'.  Commands which are
                  substituted have all blanks, tabs, and newlines preserved,
                  except for the final newline which is dropped.  The resultant
                  text is placed in an anonymous temporary file which is given

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                                  14 February 2012

                  to the command as standard input.
          > name
          >! name
          >& name
          >&! name
                  The file name is used as standard output.  If the file does
                  not exist then it is created; if the file exists, it is
                  truncated, its previous contents being lost.

                  If the shell variable noclobber is set, then the file must not
                  exist or be a character special file (e.g., a terminal or
                  `/dev/null') or an error results.  This helps prevent
                  accidental destruction of files.  In this case the `!' forms
                  can be used to suppress this check.

                  The forms involving `&' route the diagnostic output into the
                  specified file as well as the standard output.  name is
                  expanded in the same way as `<' input filenames are.
          >> name
          >>& name
          >>! name
          >>&! name
                  Like `>', but appends output to the end of name.  If the shell
                  variable noclobber is set, then it is an error for the file
                  not to exist, unless one of the `!' forms is given.

          A command receives the environment in which the shell was invoked as
          modified by the input-output parameters and the presence of the
          command in a pipeline.  Thus, unlike some previous shells, commands
          run from a file of shell commands have no access to the text of the
          commands by default; rather they receive the original standard input
          of the shell.  The `<<' mechanism should be used to present inline
          data.  This permits shell command scripts to function as components of
          pipelines and allows the shell to block read its input.  Note that the
          default standard input for a command run detached is not the empty
          file /dev/null, but the original standard input of the shell.  If this
          is a terminal and if the process attempts to read from the terminal,
          then the process will block and the user will be notified (see Jobs).

          Diagnostic output may be directed through a pipe with the standard
          output.  Simply use the form `|&' rather than just `|'.

          The shell cannot presently redirect diagnostic output without also
          redirecting standard output, but `(command > output-file) >& error-
          file' is often an acceptable workaround.  Either output-file or
          error-file may be `/dev/tty' to send output to the terminal.

        Features
          Having described how the shell accepts, parses and executes command
          lines, we now turn to a variety of its useful features.

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                                  14 February 2012

        Control flow
          The shell contains a number of commands which can be used to regulate
          the flow of control in command files (shell scripts) and (in limited
          but useful ways) from terminal input.  These commands all operate by
          forcing the shell to reread or skip in its input and, due to the
          implementation, restrict the placement of some of the commands.

          The foreach, switch, and while statements, as well as the if-then-else
          form of the if statement, require that the major keywords appear in a
          single simple command on an input line as shown below.

          If the shell's input is not seekable, the shell buffers up input
          whenever a loop is being read and performs seeks in this internal
          buffer to accomplish the rereading implied by the loop.  (To the
          extent that this allows, backward gotos will succeed on non-seekable
          inputs.)

        Expressions
          The if, while and exit builtin commands use expressions with a common
          syntax.  The expressions can include any of the operators described in
          the next three sections.  Note that the @ builtin command (q.v.) has
          its own separate syntax.

        Logical, arithmetical and comparison operators
          These operators are similar to those of C and have the same
          precedence.  They include

              ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
              <  > <<  >>  +  -  *  /  %  !  ~  (  )

          Here the precedence increases to the right, `==' `!=' `=~' and `!~',
          `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%'
          being, in groups, at the same level.  The `==' `!=' `=~' and `!~'
          operators compare their arguments as strings; all others operate on
          numbers.  The operators `=~' and `!~' are like `!=' and `==' except
          that the right hand side is a glob-pattern (see Filename substitution)
          against which the left hand operand is matched.  This reduces the need
          for use of the switch builtin command in shell scripts when all that
          is really needed is pattern matching.

          Null or missing arguments are considered `0'.  The results of all
          expressions are strings, which represent decimal numbers.  It is
          important to note that no two components of an expression can appear
          in the same word; except when adjacent to components of expressions
          which are syntactically significant to the parser (`&' `|' `<' `>' `('
          `)') they should be surrounded by spaces.

        Command exit status
          Commands can be executed in expressions and their exit status returned
          by enclosing them in braces (`{}').  Remember that the braces should
          be separated from the words of the command by spaces.  Command

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                                  14 February 2012

          executions succeed, returning true, i.e., `1', if the command exits
          with status 0, otherwise they fail, returning false, i.e., `0'.  If
          more detailed status information is required then the command should
          be executed outside of an expression and the status shell variable
          examined.

        File inquiry operators
          Some of these operators perform true/false tests on files and related
          objects.  They are of the form -op file, where op is one of

              r   Read access
              w   Write access
              x   Execute access
              X   Executable in the path or shell builtin, e.g., `-X ls' and `-X
                  ls-F' are generally true, but `-X /bin/ls' is not (+)
              e   Existence
              o   Ownership
              z   Zero size
              s   Non-zero size (+)
              f   Plain file
              d   Directory
              l   Symbolic link (+) *
              b   Block special file (+)
              c   Character special file (+)
              p   Named pipe (fifo) (+) *
              S   Socket special file (+) *
              u   Set-user-ID bit is set (+)
              g   Set-group-ID bit is set (+)
              k   Sticky bit is set (+)
              t   file (which must be a digit) is an open file descriptor for a
                  terminal device (+)
              R   Has been migrated (Convex only) (+)
              L   Applies subsequent operators in a multiple-operator test to a
                  symbolic link rather than to the file to which the link points
                  (+) *

          file is command and filename expanded and then tested to see if it has
          the specified relationship to the real user.  If file does not exist
          or is inaccessible or, for the operators indicated by `*', if the
          specified file type does not exist on the current system, then all
          enquiries return false, i.e., `0'.

          These operators may be combined for conciseness: `-xy file' is
          equivalent to `-x file && -y file'.  (+) For example, `-fx' is true
          (returns `1') for plain executable files, but not for directories.

          L may be used in a multiple-operator test to apply subsequent
          operators to a symbolic link rather than to the file to which the link
          points.  For example, `-lLo' is true for links owned by the invoking
          user.  Lr, Lw and Lx are always true for links and false for non-
          links.  L has a different meaning when it is the last operator in a

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                                  14 February 2012

          multiple-operator test; see below.

          It is possible but not useful, and sometimes misleading, to combine
          operators which expect file to be a file with operators which do not
          (e.g., X and t).  Following L with a non-file operator can lead to
          particularly strange results.

          Other operators return other information, i.e., not just `0' or `1'.
          (+) They have the same format as before; op may be one of

              A       Last file access time, as the number of seconds since the
                      epoch
              A:      Like A, but in timestamp format, e.g., `Fri May 14
                      16:36:10 1993'
              M       Last file modification time
              M:      Like M, but in timestamp format
              C       Last inode modification time
              C:      Like C, but in timestamp format
              D       Device number
              I       Inode number
              F       Composite file identifier, in the form device:inode
              L       The name of the file pointed to by a symbolic link
              N       Number of (hard) links
              P       Permissions, in octal, without leading zero
              P:      Like P, with leading zero
              Pmode   Equivalent to `-P file & mode', e.g., `-P22 file' returns
                      `22' if file is writable by group and other, `20' if by
                      group only, and `0' if by neither
              Pmode:  Like Pmode, with leading zero
              U       Numeric userid
              U:      Username, or the numeric userid if the username is unknown
              G       Numeric groupid
              G:      Groupname, or the numeric groupid if the groupname is
                      unknown
              Z       Size, in bytes

          Only one of these operators may appear in a multiple-operator test,
          and it must be the last.  Note that L has a different meaning at the
          end of and elsewhere in a multiple-operator test.  Because `0' is a
          valid return value for many of these operators, they do not return `0'
          when they fail: most return `-1', and F returns `:'.

          If the shell is compiled with POSIX defined (see the version shell
          variable), the result of a file inquiry is based on the permission
          bits of the file and not on the result of the access(2) system call.
          For example, if one tests a file with -w whose permissions would
          ordinarily allow writing but which is on a file system mounted read-
          only, the test will succeed in a POSIX shell but fail in a non-POSIX
          shell.

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                                  14 February 2012

          File inquiry operators can also be evaluated with the filetest builtin
          command (q.v.) (+).

        Jobs
          The shell associates a job with each pipeline.  It keeps a table of
          current jobs, printed by the jobs command, and assigns them small
          integer numbers.  When a job is started asynchronously with `&', the
          shell prints a line which looks like

              [1] 1234

          indicating that the job which was started asynchronously was job
          number 1 and had one (top-level) process, whose process id was 1234.

          If you are running a job and wish to do something else you may hit the
          suspend key (usually `^Z'), which sends a STOP signal to the current
          job.  The shell will then normally indicate that the job has been
          `Suspended' and print another prompt.  If the listjobs shell variable
          is set, all jobs will be listed like the jobs builtin command; if it
          is set to `long' the listing will be in long format, like `jobs -l'.
          You can then manipulate the state of the suspended job.  You can put
          it in the ``background'' with the bg command or run some other
          commands and eventually bring the job back into the ``foreground''
          with fg.  (See also the run-fg-editor editor command.) A `^Z' takes
          effect immediately and is like an interrupt in that pending output and
          unread input are discarded when it is typed.  The wait builtin command
          causes the shell to wait for all background jobs to complete.

          The `^]' key sends a delayed suspend signal, which does not generate a
          STOP signal until a program attempts to read(2) it, to the current
          job.  This can usefully be typed ahead when you have prepared some
          commands for a job which you wish to stop after it has read them.  The
          `^Y' key performs this function in csh(1); in tcsh, `^Y' is an editing
          command.  (+)

          A job being run in the background stops if it tries to read from the
          terminal.  Background jobs are normally allowed to produce output, but
          this can be disabled by giving the command `stty tostop'.  If you set
          this tty option, then background jobs will stop when they try to
          produce output like they do when they try to read input.

          There are several ways to refer to jobs in the shell.  The character
          `%' introduces a job name.  If you wish to refer to job number 1, you
          can name it as `%1'.  Just naming a job brings it to the foreground;
          thus `%1' is a synonym for `fg %1', bringing job 1 back into the
          foreground.  Similarly, saying `%1 &' resumes job 1 in the background,
          just like `bg %1'.  A job can also be named by an unambiguous prefix
          of the string typed in to start it: `%ex' would normally restart a
          suspended ex(1) job, if there were only one suspended job whose name
          began with the string `ex'.  It is also possible to say `%?string' to
          specify a job whose text contains string, if there is only one such

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                                  14 February 2012

          job.

          The shell maintains a notion of the current and previous jobs.  In
          output pertaining to jobs, the current job is marked with a `+' and
          the previous job with a `-'.  The abbreviations `%+', `%', and (by
          analogy with the syntax of the history mechanism) `%%' all refer to
          the current job, and `%-' refers to the previous job.

          The job control mechanism requires that the stty(1) option `new' be
          set on some systems.  It is an artifact from a `new' implementation of
          the tty driver which allows generation of interrupt characters from
          the keyboard to tell jobs to stop.  See stty(1) and the setty builtin
          command for details on setting options in the new tty driver.

        Status reporting
          The shell learns immediately whenever a process changes state.  It
          normally informs you whenever a job becomes blocked so that no further
          progress is possible, but only right before it prints a prompt.  This
          is done so that it does not otherwise disturb your work.  If, however,
          you set the shell variable notify, the shell will notify you
          immediately of changes of status in background jobs.  There is also a
          shell command notify which marks a single process so that its status
          changes will be immediately reported.  By default notify marks the
          current process; simply say `notify' after starting a background job
          to mark it.

          When you try to leave the shell while jobs are stopped, you will be
          warned that `There are suspended jobs.' You may use the jobs command
          to see what they are.  If you do this or immediately try to exit
          again, the shell will not warn you a second time, and the suspended
          jobs will be terminated.

        Automatic, periodic and timed events (+)
          There are various ways to run commands and take other actions
          automatically at various times in the ``life cycle'' of the shell.
          They are summarized here, and described in detail under the
          appropriate Builtin commands, Special shell variables and Special
          aliases.

          The sched builtin command puts commands in a scheduled-event list, to
          be executed by the shell at a given time.

          The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
          aliases can be set, respectively, to execute commands when the shell
          wants to ring the bell, when the working directory changes, every
          tperiod minutes, before each prompt, before each command gets
          executed, after each command gets executed, and when a job is started
          or is brought into the foreground.

          The autologout shell variable can be set to log out or lock the shell
          after a given number of minutes of inactivity.

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          The mail shell variable can be set to check for new mail periodically.

          The printexitvalue shell variable can be set to print the exit status
          of commands which exit with a status other than zero.

          The rmstar shell variable can be set to ask the user, when `rm *' is
          typed, if that is really what was meant.

          The time shell variable can be set to execute the time builtin command
          after the completion of any process that takes more than a given
          number of CPU seconds.

          The watch and who shell variables can be set to report when selected
          users log in or out, and the log builtin command reports on those
          users at any time.

        Native Language System support (+)
          The shell is eight bit clean (if so compiled; see the version shell
          variable) and thus supports character sets needing this capability.
          NLS support differs depending on whether or not the shell was compiled
          to use the system's NLS (again, see version).  In either case, 7-bit
          ASCII is the default character code (e.g., the classification of which
          characters are printable) and sorting, and changing the LANG or
          LC_CTYPE environment variables causes a check for possible changes in
          these respects.

          When using the system's NLS, the setlocale(3) function is called to
          determine appropriate character code/classification and sorting (e.g.,
          a 'en_CA.UTF-8' would yield "UTF-8" as a character code).  This
          function typically examines the LANG and LC_CTYPE environment
          variables; refer to the system documentation for further details.
          When not using the system's NLS, the shell simulates it by assuming
          that the ISO 8859-1 character set is used whenever either of the LANG
          and LC_CTYPE variables are set, regardless of their values.  Sorting
          is not affected for the simulated NLS.

          In addition, with both real and simulated NLS, all printable
          characters in the range \200-\377, i.e., those that have M-char
          bindings, are automatically rebound to self-insert-command.  The
          corresponding binding for the escape-char sequence, if any, is left
          alone.  These characters are not rebound if the NOREBIND environment
          variable is set.  This may be useful for the simulated NLS or a
          primitive real NLS which assumes full ISO 8859-1.  Otherwise, all M-
          char bindings in the range \240-\377 are effectively undone.
          Explicitly rebinding the relevant keys with bindkey is of course still
          possible.

          Unknown characters (i.e., those that are neither printable nor control
          characters) are printed in the format \nnn.  If the tty is not in 8
          bit mode, other 8 bit characters are printed by converting them to
          ASCII and using standout mode.  The shell never changes the 7/8 bit

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                                  14 February 2012

          mode of the tty and tracks user-initiated changes of 7/8 bit mode.
          NLS users (or, for that matter, those who want to use a meta key) may
          need to explicitly set the tty in 8 bit mode through the appropriate
          stty(1) command in, e.g., the ~/.login file.

        OS variant support (+)
          A number of new builtin commands are provided to support features in
          particular operating systems.  All are described in detail in the
          Builtin commands section.

          On systems that support TCF (aix-ibm370, aix-ps2), getspath and
          setspath get and set the system execution path, getxvers and setxvers
          get and set the experimental version prefix and migrate migrates
          processes between sites.  The jobs builtin prints the site on which
          each job is executing.

          Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD
          operating system.

          Under Domain/OS, inlib adds shared libraries to the current
          environment, rootnode changes the rootnode and ver changes the
          systype.

          Under Mach, setpath is equivalent to Mach's setpath(1).

          Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

          Under Harris CX/UX, ucb or att runs a command under the specified
          universe.

          Under Convex/OS, warp prints or sets the universe.

          The VENDOR, OSTYPE and MACHTYPE environment variables indicate
          respectively the vendor, operating system and machine type
          (microprocessor class or machine model) of the system on which the
          shell thinks it is running.  These are particularly useful when
          sharing one's home directory between several types of machines; one
          can, for example,

              set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

          in one's ~/.login and put executables compiled for each machine in the
          appropriate directory.

          The version shell variable indicates what options were chosen when the
          shell was compiled.

          Note also the newgrp builtin, the afsuser and echo_style shell
          variables and the system-dependent locations of the shell's input
          files (see FILES).

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        Signal handling
          Login shells ignore interrupts when reading the file ~/.logout.  The
          shell ignores quit signals unless started with -q.  Login shells catch
          the terminate signal, but non-login shells inherit the terminate
          behavior from their parents.  Other signals have the values which the
          shell inherited from its parent.

          In shell scripts, the shell's handling of interrupt and terminate
          signals can be controlled with onintr, and its handling of hangups can
          be controlled with hup and nohup.

          The shell exits on a hangup (see also the logout shell variable).  By
          default, the shell's children do too, but the shell does not send them
          a hangup when it exits.  hup arranges for the shell to send a hangup
          to a child when it exits, and nohup sets a child to ignore hangups.

        Terminal management (+)
          The shell uses three different sets of terminal (``tty'') modes:
          `edit', used when editing, `quote', used when quoting literal
          characters, and `execute', used when executing commands.  The shell
          holds some settings in each mode constant, so commands which leave the
          tty in a confused state do not interfere with the shell.  The shell
          also matches changes in the speed and padding of the tty.  The list of
          tty modes that are kept constant can be examined and modified with the
          setty builtin.  Note that although the editor uses CBREAK mode (or its
          equivalent), it takes typed-ahead characters anyway.

          The echotc, settc and telltc commands can be used to manipulate and
          debug terminal capabilities from the command line.

          On systems that support SIGWINCH or SIGWINDOW, the shell adapts to
          window resizing automatically and adjusts the environment variables
          LINES and COLUMNS if set.  If the environment variable TERMCAP
          contains li# and co# fields, the shell adjusts them to reflect the new
          window size.

     REFERENCE
          The next sections of this manual describe all of the available Builtin
          commands, Special aliases and Special shell variables.

        Builtin commands
          %job    A synonym for the fg builtin command.

          %job &  A synonym for the bg builtin command.

          :       Does nothing, successfully.

          @
          @ name = expr
          @ name[index] = expr
          @ name++|--

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          @ name[index]++|--
                  The first form prints the values of all shell variables.

                  The second form assigns the value of expr to name.  The third
                  form assigns the value of expr to the index'th component of
                  name; both name and its index'th component must already exist.

                  expr may contain the operators `*', `+', etc., as in C.  If
                  expr contains `<', `>', `&' or `' then at least that part of
                  expr must be placed within `()'.  Note that the syntax of expr
                  has nothing to do with that described under Expressions.

                  The fourth and fifth forms increment (`++') or decrement
                  (`--') name or its index'th component.

                  The space between `@' and name is required.  The spaces
                  between name and `=' and between `=' and expr are optional.
                  Components of expr must be separated by spaces.

          alias [name [wordlist]]
                  Without arguments, prints all aliases.  With name, prints the
                  alias for name.  With name and wordlist, assigns wordlist as
                  the alias of name.  wordlist is command and filename
                  substituted.  name may not be `alias' or `unalias'.  See also
                  the unalias builtin command.

          alloc   Shows the amount of dynamic memory acquired, broken down into
                  used and free memory.  With an argument shows the number of
                  free and used blocks in each size category.  The categories
                  start at size 8 and double at each step.  This command's
                  output may vary across system types, because systems other
                  than the VAX may use a different memory allocator.

          bg [%job ...]
                  Puts the specified jobs (or, without arguments, the current
                  job) into the background, continuing each if it is stopped.
                  job may be a number, a string, `', `%', `+' or `-' as
                  described under Jobs.

          bindkey [-l|-d|-e|-v|-u] (+)
          bindkey [-a] [-b] [-k] [-r] [--] key (+)
          bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
                  Without options, the first form lists all bound keys and the
                  editor command to which each is bound, the second form lists
                  the editor command to which key is bound and the third form
                  binds the editor command command to key.  Options include:

                  -l  Lists all editor commands and a short description of each.
                  -d  Binds all keys to the standard bindings for the default
                      editor.

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                  -e  Binds all keys to the standard GNU Emacs-like bindings.
                  -v  Binds all keys to the standard vi(1)-like bindings.
                  -a  Lists or changes key-bindings in the alternative key map.
                      This is the key map used in vi command mode.
                  -b  key is interpreted as a control character written
                      ^character (e.g., `^A') or C-character (e.g., `C-A'), a
                      meta character written M-character (e.g., `M-A'), a
                      function key written F-string (e.g., `F-string'), or an
                      extended prefix key written X-character (e.g., `X-A').
                  -k  key is interpreted as a symbolic arrow key name, which may
                      be one of `down', `up', `left' or `right'.
                  -r  Removes key's binding.  Be careful: `bindkey -r' does not
                      bind key to self-insert-command (q.v.), it unbinds key
                      completely.
                  -c  command is interpreted as a builtin or external command
                      instead of an editor command.
                  -s  command is taken as a literal string and treated as
                      terminal input when key is typed.  Bound keys in command
                      are themselves reinterpreted, and this continues for ten
                      levels of interpretation.
                  --  Forces a break from option processing, so the next word is
                      taken as key even if it begins with '-'.
                  -u (or any invalid option)
                      Prints a usage message.

                  key may be a single character or a string.  If a command is
                  bound to a string, the first character of the string is bound
                  to sequence-lead-in and the entire string is bound to the
                  command.

                  Control characters in key can be literal (they can be typed by
                  preceding them with the editor command quoted-insert, normally
                  bound to `^V') or written caret-character style, e.g., `^A'.
                  Delete is written `^?' (caret-question mark).  key and command
                  can contain backslashed escape sequences (in the style of
                  System V echo(1)) as follows:

                      \a      Bell
                      \b      Backspace
                      \e      Escape
                      \f      Form feed
                      \n      Newline
                      \r      Carriage return
                      \t      Horizontal tab
                      \v      Vertical tab
                      \nnn    The ASCII character corresponding to the octal
                              number nnn

                  `\' nullifies the special meaning of the following character,
                  if it has any, notably `\' and `^'.

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          bs2cmd bs2000-command (+)
                  Passes bs2000-command to the BS2000 command interpreter for
                  execution. Only non-interactive commands can be executed, and
                  it is not possible to execute any command that would overlay
                  the image of the current process, like /EXECUTE or /CALL-
                  PROCEDURE. (BS2000 only)

          break   Causes execution to resume after the end of the nearest
                  enclosing foreach or while.  The remaining commands on the
                  current line are executed.  Multi-level breaks are thus
                  possible by writing them all on one line.

          breaksw Causes a break from a switch, resuming after the endsw.

          builtins (+)
                  Prints the names of all builtin commands.

          bye (+) A synonym for the logout builtin command.  Available only if
                  the shell was so compiled; see the version shell variable.

          case label:
                  A label in a switch statement as discussed below.

          cd [-p] [-l] [-n|-v] [I--] [name]
                  If a directory name is given, changes the shell's working
                  directory to name.  If not, changes to home.  If name is `-'
                  it is interpreted as the previous working directory (see Other
                  substitutions).  (+) If name is not a subdirectory of the
                  current directory (and does not begin with `/', `./' or
                  `../'), each component of the variable cdpath is checked to
                  see if it has a subdirectory name.  Finally, if all else fails
                  but name is a shell variable whose value begins with `/', then
                  this is tried to see if it is a directory.

                  With -p, prints the final directory stack, just like dirs.
                  The -l, -n and -v flags have the same effect on cd as on dirs,
                  and they imply -p.  (+) Using -- forces a break from option
                  processing so the next word is taken as the directory name
                  even if it begins with '-'. (+)

                  See also the implicitcd shell variable.

          chdir   A synonym for the cd builtin command.

          complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
                  Without arguments, lists all completions.  With command, lists
                  completions for command.  With command and word etc., defines
                  completions.

                  command may be a full command name or a glob-pattern (see
                  Filename substitution).  It can begin with `-' to indicate

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                  that completion should be used only when command is ambiguous.

                  word specifies which word relative to the current word is to
                  be completed, and may be one of the following:

                      c   Current-word completion.  pattern is a glob-pattern
                          which must match the beginning of the current word on
                          the command line.  pattern is ignored when completing
                          the current word.
                      C   Like c, but includes pattern when completing the
                          current word.
                      n   Next-word completion.  pattern is a glob-pattern which
                          must match the beginning of the previous word on the
                          command line.
                      N   Like n, but must match the beginning of the word two
                          before the current word.
                      p   Position-dependent completion.  pattern is a numeric
                          range, with the same syntax used to index shell
                          variables, which must include the current word.

                  list, the list of possible completions, may be one of the
                  following:

                      a       Aliases
                      b       Bindings (editor commands)
                      c       Commands (builtin or external commands)
                      C       External commands which begin with the supplied
                              path prefix
                      d       Directories
                      D       Directories which begin with the supplied path
                              prefix
                      e       Environment variables
                      f       Filenames
                      F       Filenames which begin with the supplied path
                              prefix
                      g       Groupnames
                      j       Jobs
                      l       Limits
                      n       Nothing
                      s       Shell variables
                      S       Signals
                      t       Plain (``text'') files
                      T       Plain (``text'') files which begin with the
                              supplied path prefix
                      v       Any variables
                      u       Usernames
                      x       Like n, but prints select when list-choices is
                              used.
                      X       Completions
                      $var    Words from the variable var

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                      (...)   Words from the given list
                      `...`   Words from the output of command

                  select is an optional glob-pattern.  If given, words from only
                  list that match select are considered and the fignore shell
                  variable is ignored.  The last three types of completion may
                  not have a select pattern, and x uses select as an explanatory
                  message when the list-choices editor command is used.

                  suffix is a single character to be appended to a successful
                  completion.  If null, no character is appended.  If omitted
                  (in which case the fourth delimiter can also be omitted), a
                  slash is appended to directories and a space to other words.

                  command invoked from `...` version has additional environment
                  variable set, the variable name is COMMAND_LINE and contains
                  (as its name indicates) contents of the current (already typed
                  in) command line. One can examine and use contents of the
                  COMMAND_LINE variable in her custom script to build more
                  sophisticated completions (see completion for svn(1) included
                  in this package).

                  Now for some examples.  Some commands take only directories as
                  arguments, so there's no point completing plain files.

                      > complete cd 'p/1/d/'

                  completes only the first word following `cd' (`p/1') with a
                  directory.  p-type completion can also be used to narrow down
                  command completion:

                      > co[^D]
                      complete compress
                      > complete -co* 'p/0/(compress)/'
                      > co[^D]
                      > compress

                  This completion completes commands (words in position 0,
                  `p/0') which begin with `co' (thus matching `co*') to
                  `compress' (the only word in the list).  The leading `-'
                  indicates that this completion is to be used with only
                  ambiguous commands.

                      > complete find 'n/-user/u/'

                  is an example of n-type completion.  Any word following `find'
                  and immediately following `-user' is completed from the list
                  of users.

                      > complete cc 'c/-I/d/'

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                  demonstrates c-type completion.  Any word following `cc' and
                  beginning with `-I' is completed as a directory.  `-I' is not
                  taken as part of the directory because we used lowercase c.

                  Different lists are useful with different commands.

                      > complete alias 'p/1/a/'
                      > complete man 'p/*/c/'
                      > complete set 'p/1/s/'
                      > complete true 'p/1/x:Truth has no options./'

                  These complete words following `alias' with aliases, `man'
                  with commands, and `set' with shell variables.  `true' doesn't
                  have any options, so x does nothing when completion is
                  attempted and prints `Truth has no options.' when completion
                  choices are listed.

                  Note that the man example, and several other examples below,
                  could just as well have used 'c/*' or 'n/*' as 'p/*'.

                  Words can be completed from a variable evaluated at completion
                  time,

                      > complete ftp 'p/1/$hostnames/'
                      > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
                      > ftp [^D]
                      rtfm.mit.edu tesla.ee.cornell.edu
                      > ftp [^C]
                      > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
                      uunet.uu.net)
                      > ftp [^D]
                      rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

                  or from a command run at completion time:

                      > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                      > kill -9 [^D]
                      23113 23377 23380 23406 23429 23529 23530 PID

                  Note that the complete command does not itself quote its
                  arguments, so the braces, space and `$' in `{print $1}' must
                  be quoted explicitly.

                  One command can have multiple completions:

                      > complete dbx 'p/2/(core)/' 'p/*/c/'

                  completes the second argument to `dbx' with the word `core'
                  and all other arguments with commands.  Note that the
                  positional completion is specified before the next-word
                  completion.  Because completions are evaluated from left to

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                  right, if the next-word completion were specified first it
                  would always match and the positional completion would never
                  be executed.  This is a common mistake when defining a
                  completion.

                  The select pattern is useful when a command takes files with
                  only particular forms as arguments.  For example,

                      > complete cc 'p/*/f:*.[cao]/'

                  completes `cc' arguments to files ending in only `.c', `.a',
                  or `.o'.  select can also exclude files, using negation of a
                  glob-pattern as described under Filename substitution.  One
                  might use

                      > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

                  to exclude precious source code from `rm' completion.  Of
                  course, one could still type excluded names manually or
                  override the completion mechanism using the complete-word-raw
                  or list-choices-raw editor commands (q.v.).

                  The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
                  respectively, but they use the select argument in a different
                  way: to restrict completion to files beginning with a
                  particular path prefix.  For example, the Elm mail program
                  uses `=' as an abbreviation for one's mail directory.  One
                  might use

                      > complete elm c@=@F:$HOME/Mail/@

                  to complete `elm -f =' as if it were `elm -f ~/Mail/'.  Note
                  that we used `@' instead of `/' to avoid confusion with the
                  select argument, and we used `$HOME' instead of `~' because
                  home directory substitution works at only the beginning of a
                  word.

                  suffix is used to add a nonstandard suffix (not space or `/'
                  for directories) to completed words.

                      > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

                  completes arguments to `finger' from the list of users,
                  appends an `@', and then completes after the `@' from the
                  `hostnames' variable.  Note again the order in which the
                  completions are specified.

                  Finally, here's a complex example for inspiration:

                      > complete find \
                      'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \

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                      'n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                      'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                      'n/-type/(b c d f l p s)/' \
                      'c/-/(name newer cpio ncpio exec ok user \
                      group fstype type atime ctime depth inum \
                      ls mtime nogroup nouser perm print prune \
                      size xdev)/' \
                      'p/*/d/'

                  This completes words following `-name', `-newer', `-cpio' or
                  `ncpio' (note the pattern which matches both) to files, words
                  following `-exec' or `-ok' to commands, words following `user'
                  and `group' to users and groups respectively and words
                  following `-fstype' or `-type' to members of the given lists.
                  It also completes the switches themselves from the given list
                  (note the use of c-type completion) and completes anything not
                  otherwise completed to a directory.  Whew.

                  Remember that programmed completions are ignored if the word
                  being completed is a tilde substitution (beginning with `~')
                  or a variable (beginning with `$').  complete is an
                  experimental feature, and the syntax may change in future
                  versions of the shell.  See also the uncomplete builtin
                  command.

          continue
                  Continues execution of the nearest enclosing while or foreach.
                  The rest of the commands on the current line are executed.

          default:
                  Labels the default case in a switch statement.  It should come
                  after all case labels.

          dirs [-l] [-n|-v]
          dirs -S|-L [filename] (+)
          dirs -c (+)
                  The first form prints the directory stack.  The top of the
                  stack is at the left and the first directory in the stack is
                  the current directory.  With -l, `~' or `~name' in the output
                  is expanded explicitly to home or the pathname of the home
                  directory for user name.  (+) With -n, entries are wrapped
                  before they reach the edge of the screen.  (+) With -v,
                  entries are printed one per line, preceded by their stack
                  positions.  (+) If more than one of -n or -v is given, -v
                  takes precedence.  -p is accepted but does nothing.

                  With -S, the second form saves the directory stack to filename
                  as a series of cd and pushd commands.  With -L, the shell
                  sources filename, which is presumably a directory stack file
                  saved by the -S option or the savedirs mechanism.  In either
                  case, dirsfile is used if filename is not given and ~/.cshdirs

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                  is used if dirsfile is unset.

                  Note that login shells do the equivalent of `dirs -L' on
                  startup and, if savedirs is set, `dirs -S' before exiting.
                  Because only ~/.tcshrc is normally sourced before ~/.cshdirs,
                  dirsfile should be set in ~/.tcshrc rather than ~/.login.

                  The last form clears the directory stack.

          echo [-n] word ...
                  Writes each word to the shell's standard output, separated by
                  spaces and terminated with a newline.  The echo_style shell
                  variable may be set to emulate (or not) the flags and escape
                  sequences of the BSD and/or System V versions of echo; see
                  echo(1).

          echotc [-sv] arg ... (+)
                  Exercises the terminal capabilities (see termcap(5)) in args.
                  For example, 'echotc home' sends the cursor to the home
                  position, 'echotc cm 3 10' sends it to column 3 and row 10,
                  and 'echotc ts 0; echo "This is a test."; echotc fs' prints
                  "This is a test." in the status line.

                  If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints
                  the value of that capability ("yes" or "no" indicating that
                  the terminal does or does not have that capability).  One
                  might use this to make the output from a shell script less
                  verbose on slow terminals, or limit command output to the
                  number of lines on the screen:

                      > set history=`echotc lines`
                      > @ history--

                  Termcap strings may contain wildcards which will not echo
                  correctly.  One should use double quotes when setting a shell
                  variable to a terminal capability string, as in the following
                  example that places the date in the status line:

                      > set tosl="`echotc ts 0`"
                      > set frsl="`echotc fs`"
                      > echo -n "$tosl";date; echo -n "$frsl"

                  With -s, nonexistent capabilities return the empty string
                  rather than causing an error.  With -v, messages are verbose.

          else
          end
          endif
          endsw   See the description of the foreach, if, switch, and while
                  statements below.

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          eval arg ...
                  Treats the arguments as input to the shell and executes the
                  resulting command(s) in the context of the current shell.
                  This is usually used to execute commands generated as the
                  result of command or variable substitution, because parsing
                  occurs before these substitutions.  See tset(1) for a sample
                  use of eval.

          exec command
                  Executes the specified command in place of the current shell.

          exit [expr]
                  The shell exits either with the value of the specified expr
                  (an expression, as described under Expressions) or, without
                  expr, with the value 0.

          fg [%job ...]
                  Brings the specified jobs (or, without arguments, the current
                  job) into the foreground, continuing each if it is stopped.
                  job may be a number, a string, `', `%', `+' or `-' as
                  described under Jobs.  See also the run-fg-editor editor
                  command.

          filetest -op file ... (+)
                  Applies op (which is a file inquiry operator as described
                  under File inquiry operators) to each file and returns the
                  results as a space-separated list.

          foreach name (wordlist)
          ...
          end     Successively sets the variable name to each member of wordlist
                  and executes the sequence of commands between this command and
                  the matching end.  (Both foreach and end must appear alone on
                  separate lines.)  The builtin command continue may be used to
                  continue the loop prematurely and the builtin command break to
                  terminate it prematurely.  When this command is read from the
                  terminal, the loop is read once prompting with `foreach? ' (or
                  prompt2) before any statements in the loop are executed.  If
                  you make a mistake typing in a loop at the terminal you can
                  rub it out.

          getspath (+)
                  Prints the system execution path.  (TCF only)

          getxvers (+)
                  Prints the experimental version prefix.  (TCF only)

          glob wordlist
                  Like echo, but the `-n' parameter is not recognized and words
                  are delimited by null characters in the output.  Useful for
                  programs which wish to use the shell to filename expand a list

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                  of words.

          goto word
                  word is filename and command-substituted to yield a string of
                  the form `label'.  The shell rewinds its input as much as
                  possible, searches for a line of the form `label:', possibly
                  preceded by blanks or tabs, and continues execution after that
                  line.

          hashstat
                  Prints a statistics line indicating how effective the internal
                  hash table has been at locating commands (and avoiding
                  exec's).  An exec is attempted for each component of the path
                  where the hash function indicates a possible hit, and in each
                  component which does not begin with a `/'.

                  On machines without vfork(2), prints only the number and size
                  of hash buckets.

          history [-hTr] [n]
          history -S|-L|-M [filename] (+)
          history -c (+)
                  The first form prints the history event list.  If n is given
                  only the n most recent events are printed or saved.  With -h,
                  the history list is printed without leading numbers.  If -T is
                  specified, timestamps are printed also in comment form.  (This
                  can be used to produce files suitable for loading with
                  'history -L' or 'source -h'.) With -r, the order of printing
                  is most recent first rather than oldest first.

                  With -S, the second form saves the history list to filename.
                  If the first word of the savehist shell variable is set to a
                  number, at most that many lines are saved.  If the second word
                  of savehist is set to `merge', the history list is merged with
                  the existing history file instead of replacing it (if there is
                  one) and sorted by time stamp.  (+) Merging is intended for an
                  environment like the X Window System with several shells in
                  simultaneous use.  Currently it succeeds only when the shells
                  quit nicely one after another.

                  With -L, the shell appends filename, which is presumably a
                  history list saved by the -S option or the savehist mechanism,
                  to the history list.  -M is like -L, but the contents of
                  filename are merged into the history list and sorted by
                  timestamp.  In either case, histfile is used if filename is
                  not given and ~/.history is used if histfile is unset.
                  `history -L' is exactly like 'source -h' except that it does
                  not require a filename.

                  Note that login shells do the equivalent of `history -L' on
                  startup and, if savehist is set, `history -S' before exiting.

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                  Because only ~/.tcshrc is normally sourced before ~/.history,
                  histfile should be set in ~/.tcshrc rather than ~/.login.

                  If histlit is set, the first and second forms print and save
                  the literal (unexpanded) form of the history list.

                  The last form clears the history list.

          hup [command] (+)
                  With command, runs command such that it will exit on a hangup
                  signal and arranges for the shell to send it a hangup signal
                  when the shell exits.  Note that commands may set their own
                  response to hangups, overriding hup.  Without an argument,
                  causes the non-interactive shell only to exit on a hangup for
                  the remainder of the script.  See also Signal handling and the
                  nohup builtin command.

          if (expr) command
                  If expr (an expression, as described under Expressions)
                  evaluates true, then command is executed.  Variable
                  substitution on command happens early, at the same time it
                  does for the rest of the if command.  command must be a simple
                  command, not an alias, a pipeline, a command list or a
                  parenthesized command list, but it may have arguments.
                  Input/output redirection occurs even if expr is false and
                  command is thus not executed; this is a bug.

          if (expr) then
          ...
          else if (expr2) then
          ...
          else
          ...
          endif   If the specified expr is true then the commands to the first
                  else are executed; otherwise if expr2 is true then the
                  commands to the second else are executed, etc.  Any number of
                  else-if pairs are possible; only one endif is needed.  The
                  else part is likewise optional.  (The words else and endif
                  must appear at the beginning of input lines; the if must
                  appear alone on its input line or after an else.)

          inlib shared-library ... (+)
                  Adds each shared-library to the current environment.  There is
                  no way to remove a shared library.  (Domain/OS only)

          jobs [-l]
                  Lists the active jobs.  With -l, lists process IDs in addition
                  to the normal information.  On TCF systems, prints the site on
                  which each job is executing.

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                                  14 February 2012

          kill [-s signal] %job|pid ...
          kill -l The first and second forms sends the specified signal (or, if
                  none is given, the TERM (terminate) signal) to the specified
                  jobs or processes.  job may be a number, a string, `', `%',
                  `+' or `-' as described under Jobs.  Signals are either given
                  by number or by name (as given in /usr/include/signal.h,
                  stripped of the prefix `SIG').  There is no default job;
                  saying just `kill' does not send a signal to the current job.
                  If the signal being sent is TERM (terminate) or HUP (hangup),
                  then the job or process is sent a CONT (continue) signal as
                  well.  The third form lists the signal names.

          limit [-h] [resource [maximum-use]]
                  Limits the consumption by the current process and each process
                  it creates to not individually exceed maximum-use on the
                  specified resource.  If no maximum-use is given, then the
                  current limit is printed; if no resource is given, then all
                  limitations are given.  If the -h flag is given, the hard
                  limits are used instead of the current limits.  The hard
                  limits impose a ceiling on the values of the current limits.
                  Only the super-user may raise the hard limits, but a user may
                  lower or raise the current limits within the legal range.

                  Controllable resources currently include (if supported by the
                  OS):

                  cputime
                       the maximum number of cpu-seconds to be used by each
                       process

                  filesize
                       the largest single file which can be created

                  datasize
                       the maximum growth of the data+stack region via sbrk(2)
                       beyond the end of the program text

                  stacksize
                       the maximum size of the automatically-extended stack
                       region

                  coredumpsize
                       the size of the largest core dump that will be created

                  memoryuse
                       the maximum amount of physical memory a process may have
                       allocated to it at a given time

                  vmemoryuse
                       the maximum amount of virtual memory a process may have
                       allocated to it at a given time (address space)

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                                  14 February 2012

                  vmemoryuse
                       the maximum amount of virtual memory a process may have
                       allocated to it at a given time

                  heapsize
                       the maximum amount of memory a process may allocate per
                       brk() system call

                  descriptors or openfiles
                       the maximum number of open files for this process

                  concurrency
                       the maximum number of threads for this process

                  memorylocked
                       the maximum size which a process may lock into memory
                       using mlock(2)

                  maxproc
                       the maximum number of simultaneous processes for this
                       user id

                  sbsize
                       the maximum size of socket buffer usage for this user

                  swapsize
                       the maximum amount of swap space reserved or used for
                       this user

                  maxlocks
                       the maximum number of locks for this user

                  maxsignal
                       the maximum number of pending signals for this user

                  maxmessage
                       the maximum number of bytes in POSIX mqueues for this
                       user

                  maxnice
                       the maximum nice priority the user is allowed to raise
                       mapped from [19...-20] to [0...39] for this user

                  maxrtprio
                       the maximum realtime priority for this user maxrttime the
                       timeout for RT tasks in microseconds for this user.

                  maximum-use may be given as a (floating point or integer)
                  number followed by a scale factor.  For all limits other than
                  cputime the default scale is `k' or `kilobytes' (1024 bytes);
                  a scale factor of `m' or `megabytes' or `g' or `gigabytes' may

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                                  14 February 2012

                  also be used.  For cputime the default scaling is `seconds',
                  while `m' for minutes or `h' for hours, or a time of the form
                  `mm:ss' giving minutes and seconds may be used.

                  If maximum-use  is `unlimited', then the limitation on the
                  specified resource is removed (this is equivalent to the
                  unlimit builtin command).

                  For both resource names and scale factors, unambiguous
                  prefixes of the names suffice.

          log (+) Prints the watch shell variable and reports on each user
                  indicated in watch who is logged in, regardless of when they
                  last logged in.  See also watchlog.

          login   Terminates a login shell, replacing it with an instance of
                  /bin/login. This is one way to log off, included for
                  compatibility with sh(1).

          logout  Terminates a login shell.  Especially useful if ignoreeof is
                  set.

          ls-F [-switch ...] [file ...] (+)
                  Lists files like `ls -F', but much faster.  It identifies each
                  type of special file in the listing with a special character:

                  /   Directory
                  *   Executable
                  #   Block device
                  %   Character device
                  |   Named pipe (systems with named pipes only)
                  =   Socket (systems with sockets only)
                  @   Symbolic link (systems with symbolic links only)
                  +   Hidden directory (AIX only) or context dependent (HP/UX
                      only)
                  :   Network special (HP/UX only)

                  If the listlinks shell variable is set, symbolic links are
                  identified in more detail (on only systems that have them, of
                  course):

                  @   Symbolic link to a non-directory
                  >   Symbolic link to a directory
                  &   Symbolic link to nowhere

                  listlinks also slows down ls-F and causes partitions holding
                  files pointed to by symbolic links to be mounted.

                  If the listflags shell variable is set to `x', `a' or `A', or
                  any combination thereof (e.g., `xA'), they are used as flags
                  to ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a

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                                  14 February 2012

                  combination (e.g., `ls -FxA').  On machines where `ls -C' is
                  not the default, ls-F acts like `ls -CF', unless listflags
                  contains an `x', in which case it acts like `ls -xF'.  ls-F
                  passes its arguments to ls(1) if it is given any switches, so
                  `alias ls ls-F' generally does the right thing.

                  The ls-F builtin can list files using different colors
                  depending on the filetype or extension.  See the color shell
                  variable and the LS_COLORS environment variable.

          migrate [-site] pid|%jobid ... (+)
          migrate -site (+)
                  The first form migrates the process or job to the site
                  specified or the default site determined by the system path.
                  The second form is equivalent to `migrate -site $$': it
                  migrates the current process to the specified site.  Migrating
                  the shell itself can cause unexpected behavior, because the
                  shell does not like to lose its tty.  (TCF only)

          newgrp [-] [group] (+)
                  Equivalent to `exec newgrp'; see newgrp(1).  Available only if
                  the shell was so compiled; see the version shell variable.

          nice [+number] [command]
                  Sets the scheduling priority for the shell to number, or,
                  without number, to 4.  With command, runs command at the
                  appropriate priority.  The greater the number, the less cpu
                  the process gets.  The super-user may specify negative
                  priority by using `nice -number ...'.  Command is always
                  executed in a sub-shell, and the restrictions placed on
                  commands in simple if statements apply.

          nohup [command]
                  With command, runs command such that it will ignore hangup
                  signals.  Note that commands may set their own response to
                  hangups, overriding nohup.  Without an argument, causes the
                  non-interactive shell only to ignore hangups for the remainder
                  of the script.  See also Signal handling and the hup builtin
                  command.

          notify [%job ...]
                  Causes the shell to notify the user asynchronously when the
                  status of any of the specified jobs (or, without %job, the
                  current job) changes, instead of waiting until the next prompt
                  as is usual.  job may be a number, a string, `', `%', `+' or
                  `-' as described under Jobs.  See also the notify shell
                  variable.

          onintr [-|label]
                  Controls the action of the shell on interrupts.  Without
                  arguments, restores the default action of the shell on

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                                  14 February 2012

                  interrupts, which is to terminate shell scripts or to return
                  to the terminal command input level.  With `-', causes all
                  interrupts to be ignored.  With label, causes the shell to
                  execute a `goto label' when an interrupt is received or a
                  child process terminates because it was interrupted.

                  onintr is ignored if the shell is running detached and in
                  system startup files (see FILES), where interrupts are
                  disabled anyway.

          popd [-p] [-l] [-n|-v] [+n]
                  Without arguments, pops the directory stack and returns to the
                  new top directory.  With a number `+n', discards the n'th
                  entry in the stack.

                  Finally, all forms of popd print the final directory stack,
                  just like dirs.  The pushdsilent shell variable can be set to
                  prevent this and the -p flag can be given to override
                  pushdsilent.  The -l, -n and -v flags have the same effect on
                  popd as on dirs.  (+)

          printenv [name] (+)
                  Prints the names and values of all environment variables or,
                  with name, the value of the environment variable name.

          pushd [-p] [-l] [-n|-v] [name|+n]
                  Without arguments, exchanges the top two elements of the
                  directory stack.  If pushdtohome is set, pushd without
                  arguments does `pushd ~', like cd.  (+) With name, pushes the
                  current working directory onto the directory stack and changes
                  to name.  If name is `-' it is interpreted as the previous
                  working directory (see Filename substitution).  (+) If dunique
                  is set, pushd removes any instances of name from the stack
                  before pushing it onto the stack.  (+) With a number `+n',
                  rotates the nth element of the directory stack around to be
                  the top element and changes to it.  If dextract is set,
                  however, `pushd +n' extracts the nth directory, pushes it onto
                  the top of the stack and changes to it.  (+)

                  Finally, all forms of pushd print the final directory stack,
                  just like dirs.  The pushdsilent shell variable can be set to
                  prevent this and the -p flag can be given to override
                  pushdsilent.  The -l, -n and -v flags have the same effect on
                  pushd as on dirs.  (+)

          rehash  Causes the internal hash table of the contents of the
                  directories in the path variable to be recomputed.  This is
                  needed if the autorehash shell variable is not set and new
                  commands are added to directories in path while you are logged
                  in.  With autorehash, a new command will be found
                  automatically, except in the special case where another

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                                  14 February 2012

                  command of the same name which is located in a different
                  directory already exists in the hash table.  Also flushes the
                  cache of home directories built by tilde expansion.

          repeat count command
                  The specified command, which is subject to the same
                  restrictions as the command in the one line if statement
                  above, is executed count times.  I/O redirections occur
                  exactly once, even if count is 0.

          rootnode //nodename (+)
                  Changes the rootnode to //nodename, so that `/' will be
                  interpreted as `//nodename'.  (Domain/OS only)

          sched (+)
          sched [+]hh:mm command (+)
          sched -n (+)
                  The first form prints the scheduled-event list.  The sched
                  shell variable may be set to define the format in which the
                  scheduled-event list is printed.  The second form adds command
                  to the scheduled-event list.  For example,

                      > sched 11:00 echo It\'s eleven o\'clock.

                  causes the shell to echo `It's eleven o'clock.' at 11 AM.  The
                  time may be in 12-hour AM/PM format

                      > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

                  or may be relative to the current time:

                      > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

                  A relative time specification may not use AM/PM format.  The
                  third form removes item n from the event list:

                      > sched
                           1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                           2  Wed Apr  4 17:00  set prompt=[%h] It's after 5; go
                      home: >
                      > sched -2
                      > sched
                           1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

                  A command in the scheduled-event list is executed just before
                  the first prompt is printed after the time when the command is
                  scheduled.  It is possible to miss the exact time when the
                  command is to be run, but an overdue command will execute at
                  the next prompt.  A command which comes due while the shell is
                  waiting for user input is executed immediately.  However,
                  normal operation of an already-running command will not be

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                                  14 February 2012

                  interrupted so that a scheduled-event list element may be run.

                  This mechanism is similar to, but not the same as, the at(1)
                  command on some Unix systems.  Its major disadvantage is that
                  it may not run a command at exactly the specified time.  Its
                  major advantage is that because sched runs directly from the
                  shell, it has access to shell variables and other structures.
                  This provides a mechanism for changing one's working
                  environment based on the time of day.

          set
          set name ...
          set name=word ...
          set [-r] [-f|-l] name=(wordlist) ... (+)
          set name[index]=word ...
          set -r (+)
          set -r name ... (+)
          set -r name=word ... (+)
                  The first form of the command prints the value of all shell
                  variables.  Variables which contain more than a single word
                  print as a parenthesized word list.  The second form sets name
                  to the null string.  The third form sets name to the single
                  word.  The fourth form sets name to the list of words in
                  wordlist.  In all cases the value is command and filename
                  expanded.  If -r is specified, the value is set read-only.  If
                  -f or -l are specified, set only unique words keeping their
                  order.  -f prefers the first occurrence of a word, and -l the
                  last.  The fifth form sets the index'th component of name to
                  word; this component must already exist.  The sixth form lists
                  only the names of all shell variables that are read-only.  The
                  seventh form makes name read-only, whether or not it has a
                  value.  The eighth form is the same as the third form, but
                  make name read-only at the same time.

                  These arguments can be repeated to set and/or make read-only
                  multiple variables in a single set command.  Note, however,
                  that variable expansion happens for all arguments before any
                  setting occurs.  Note also that `=' can be adjacent to both
                  name and word or separated from both by whitespace, but cannot
                  be adjacent to only one or the other.  See also the unset
                  builtin command.

          setenv [name [value]]
                  Without arguments, prints the names and values of all
                  environment variables.  Given name, sets the environment
                  variable name to value or, without value, to the null string.

          setpath path (+)
                  Equivalent to setpath(1).  (Mach only)

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                                  14 February 2012

          setspath LOCAL|site|cpu ... (+)
                  Sets the system execution path.  (TCF only)

          settc cap value (+)
                  Tells the shell to believe that the terminal capability cap
                  (as defined in termcap(5)) has the value value.  No sanity
                  checking is done.  Concept terminal users may have to `settc
                  xn no' to get proper wrapping at the rightmost column.

          setty [-d|-q|-x] [-a] [[+|-]mode] (+)
                  Controls which tty modes (see Terminal management) the shell
                  does not allow to change.  -d, -q or -x tells setty to act on
                  the `edit', `quote' or `execute' set of tty modes
                  respectively; without -d, -q or -x, `execute' is used.

                  Without other arguments, setty lists the modes in the chosen
                  set which are fixed on (`+mode') or off (`-mode').  The
                  available modes, and thus the display, vary from system to
                  system.  With -a, lists all tty modes in the chosen set
                  whether or not they are fixed.  With +mode, -mode or mode,
                  fixes mode on or off or removes control from mode in the
                  chosen set.  For example, `setty +echok echoe' fixes `echok'
                  mode on and allows commands to turn `echoe' mode on or off,
                  both when the shell is executing commands.

          setxvers [string] (+)
                  Set the experimental version prefix to string, or removes it
                  if string is omitted.  (TCF only)

          shift [variable]
                  Without arguments, discards argv[1] and shifts the members of
                  argv to the left.  It is an error for argv not to be set or to
                  have less than one word as value.  With variable, performs the
                  same function on variable.

          source [-h] name [args ...]
                  The shell reads and executes commands from name.  The commands
                  are not placed on the history list.  If any args are given,
                  they are placed in argv.  (+) source commands may be nested;
                  if they are nested too deeply the shell may run out of file
                  descriptors.  An error in a source at any level terminates all
                  nested source commands.  With -h, commands are placed on the
                  history list instead of being executed, much like `history
                  -L'.

          stop %job|pid ...
                  Stops the specified jobs or processes which are executing in
                  the background.  job may be a number, a string, `', `%', `+'
                  or `-' as described under Jobs.  There is no default job;
                  saying just `stop' does not stop the current job.

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                                  14 February 2012

          suspend Causes the shell to stop in its tracks, much as if it had been
                  sent a stop signal with ^Z.  This is most often used to stop
                  shells started by su(1).

          switch (string)
          case str1:
              ...
              breaksw
          ...
          default:
              ...
              breaksw
          endsw   Each case label is successively matched, against the specified
                  string which is first command and filename expanded.  The file
                  metacharacters `*', `?' and `[...]'  may be used in the case
                  labels, which are variable expanded.  If none of the labels
                  match before a `default' label is found, then the execution
                  begins after the default label.  Each case label and the
                  default label must appear at the beginning of a line.  The
                  command breaksw causes execution to continue after the endsw.
                  Otherwise control may fall through case labels and default
                  labels as in C.  If no label matches and there is no default,
                  execution continues after the endsw.

          telltc (+)
                  Lists the values of all terminal capabilities (see
                  termcap(5)).

          termname [terminal type] (+)
                  Tests if terminal type (or the current value of TERM if no
                  terminal type is given) has an entry in the hosts termcap(5)
                  or terminfo(5) database. Prints the terminal type to stdout
                  and returns 0 if an entry is present otherwise returns 1.

          time [command]
                  Executes command (which must be a simple command, not an
                  alias, a pipeline, a command list or a parenthesized command
                  list) and prints a time summary as described under the time
                  variable.  If necessary, an extra shell is created to print
                  the time statistic when the command completes.  Without
                  command, prints a time summary for the current shell and its
                  children.

          umask [value]
                  Sets the file creation mask to value, which is given in octal.
                  Common values for the mask are 002, giving all access to the
                  group and read and execute access to others, and 022, giving
                  read and execute access to the group and others.  Without
                  value, prints the current file creation mask.

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                                  14 February 2012

          unalias pattern
                  Removes all aliases whose names match pattern.  `unalias *'
                  thus removes all aliases.  It is not an error for nothing to
                  be unaliased.

          uncomplete pattern (+)
                  Removes all completions whose names match pattern.
                  `uncomplete *' thus removes all completions.  It is not an
                  error for nothing to be uncompleted.

          unhash  Disables use of the internal hash table to speed location of
                  executed programs.

          universe universe (+)
                  Sets the universe to universe.  (Masscomp/RTU only)

          unlimit [-hf] [resource]
                  Removes the limitation on resource or, if no resource is
                  specified, all resource limitations.  With -h, the
                  corresponding hard limits are removed.  Only the super-user
                  may do this.  Note that unlimit may not exit successful, since
                  most systems do not allow descriptors to be unlimited.  With
                  -f errors are ignored.

          unset pattern
                  Removes all variables whose names match pattern, unless they
                  are read-only.  `unset *' thus removes all variables unless
                  they are read-only; this is a bad idea.  It is not an error
                  for nothing to be unset.

          unsetenv pattern
                  Removes all environment variables whose names match pattern.
                  `unsetenv *' thus removes all environment variables; this is a
                  bad idea.  It is not an error for nothing to be unsetenved.

          ver [systype [command]] (+)
                  Without arguments, prints SYSTYPE.  With systype, sets SYSTYPE
                  to systype.  With systype and command, executes command under
                  systype.  systype may be `bsd4.3' or `sys5.3'.  (Domain/OS
                  only)

          wait    The shell waits for all background jobs.  If the shell is
                  interactive, an interrupt will disrupt the wait and cause the
                  shell to print the names and job numbers of all outstanding
                  jobs.

          warp universe (+)
                  Sets the universe to universe.  (Convex/OS only)

          watchlog (+)
                  An alternate name for the log builtin command (q.v.).

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                                  14 February 2012

                  Available only if the shell was so compiled; see the version
                  shell variable.

          where command (+)
                  Reports all known instances of command, including aliases,
                  builtins and executables in path.

          which command (+)
                  Displays the command that will be executed by the shell after
                  substitutions, path searching, etc.  The builtin command is
                  just like which(1), but it correctly reports tcsh aliases and
                  builtins and is 10 to 100 times faster.  See also the which-
                  command editor command.

          while (expr)
          ...
          end     Executes the commands between the while and the matching end
                  while expr (an expression, as described under Expressions)
                  evaluates non-zero.  while and end must appear alone on their
                  input lines.  break and continue may be used to terminate or
                  continue the loop prematurely.  If the input is a terminal,
                  the user is prompted the first time through the loop as with
                  foreach.

        Special aliases (+)
          If set, each of these aliases executes automatically at the indicated
          time.  They are all initially undefined.

          beepcmd Runs when the shell wants to ring the terminal bell.

          cwdcmd  Runs after every change of working directory.  For example, if
                  the user is working on an X window system using xterm(1) and a
                  re-parenting window manager that supports title bars such as
                  twm(1) and does

                      > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

                  then the shell will change the title of the running xterm(1)
                  to be the name of the host, a colon, and the full current
                  working directory.  A fancier way to do that is

                      > alias cwdcmd 'echo -n
                      "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

                  This will put the hostname and working directory on the title
                  bar but only the hostname in the icon manager menu.

                  Note that putting a cd, pushd or popd in cwdcmd may cause an
                  infinite loop.  It is the author's opinion that anyone doing
                  so will get what they deserve.

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                                  14 February 2012

          jobcmd  Runs before each command gets executed, or when the command
                  changes state.  This is similar to postcmd, but it does not
                  print builtins.

                      > alias jobcmd  'echo -n "^[]2\;\!#:q^G"'

                  then executing vi foo.c will put the command string in the
                  xterm title bar.

          helpcommand
                  Invoked by the run-help editor command.  The command name for
                  which help is sought is passed as sole argument.  For example,
                  if one does

                      > alias helpcommand '\!:1 --help'

                  then the help display of the command itself will be invoked,
                  using the GNU help calling convention.  Currently there is no
                  easy way to account for various calling conventions (e.g., the
                  customary Unix `-h'), except by using a table of many
                  commands.

          periodic
                  Runs every tperiod minutes.  This provides a convenient means
                  for checking on common but infrequent changes such as new
                  mail.  For example, if one does

                      > set tperiod = 30
                      > alias periodic checknews

                  then the checknews(1) program runs every 30 minutes.  If
                  periodic is set but tperiod is unset or set to 0, periodic
                  behaves like precmd.

          precmd  Runs just before each prompt is printed.  For example, if one
                  does

                      > alias precmd date

                  then date(1) runs just before the shell prompts for each
                  command.  There are no limits on what precmd can be set to do,
                  but discretion should be used.

          postcmd Runs before each command gets executed.

                      > alias postcmd  'echo -n "^[]2\;\!#:q^G"'

                  then executing vi foo.c will put the command string in the
                  xterm title bar.

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          shell   Specifies the interpreter for executable scripts which do not
                  themselves specify an interpreter.  The first word should be a
                  full path name to the desired interpreter (e.g., `/bin/csh' or
                  `/usr/local/bin/tcsh').

        Special shell variables
          The variables described in this section have special meaning to the
          shell.

          The shell sets addsuffix, argv, autologout, csubstnonl, command,
          echo_style, edit, gid, group, home, loginsh, oid, path, prompt,
          prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
          at startup; they do not change thereafter unless changed by the user.
          The shell updates cwd, dirstack, owd and status when necessary, and
          sets logout on logout.

          The shell synchronizes group, home, path, shlvl, term and user with
          the environment variables of the same names: whenever the environment
          variable changes the shell changes the corresponding shell variable to
          match (unless the shell variable is read-only) and vice versa.  Note
          that although cwd and PWD have identical meanings, they are not
          synchronized in this manner, and that the shell automatically
          interconverts the different formats of path and PATH.

          addsuffix (+)
                  If set, filename completion adds `/' to the end of directories
                  and a space to the end of normal files when they are matched
                  exactly.  Set by default.

          afsuser (+)
                  If set, autologout's autolock feature uses its value instead
                  of the local username for kerberos authentication.

          ampm (+)
                  If set, all times are shown in 12-hour AM/PM format.

          argv    The arguments to the shell.  Positional parameters are taken
                  from argv, i.e., `$1' is replaced by `$argv[1]', etc.  Set by
                  default, but usually empty in interactive shells.

          autocorrect (+)
                  If set, the spell-word editor command is invoked automatically
                  before each completion attempt.

          autoexpand (+)
                  If set, the expand-history editor command is invoked
                  automatically before each completion attempt. If this is set
                  to onlyhistory, then only history will be expanded and a
                  second completion will expand filenames.

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                                  14 February 2012

          autolist (+)
                  If set, possibilities are listed after an ambiguous
                  completion.  If set to `ambiguous', possibilities are listed
                  only when no new characters are added by completion.

          autologout (+)
                  The first word is the number of minutes of inactivity before
                  automatic logout.  The optional second word is the number of
                  minutes of inactivity before automatic locking.  When the
                  shell automatically logs out, it prints `auto-logout', sets
                  the variable logout to `automatic' and exits.  When the shell
                  automatically locks, the user is required to enter his
                  password to continue working.  Five incorrect attempts result
                  in automatic logout.  Set to `60' (automatic logout after 60
                  minutes, and no locking) by default in login and superuser
                  shells, but not if the shell thinks it is running under a
                  window system (i.e., the DISPLAY environment variable is set),
                  the tty is a pseudo-tty (pty) or the shell was not so compiled
                  (see the version shell variable).  See also the afsuser and
                  logout shell variables.

          autorehash (+)
                  If set, the internal hash table of the contents of the
                  directories in the path variable will be recomputed if a
                  command is not found in the hash table.  In addition, the list
                  of available commands will be rebuilt for each command
                  completion or spelling correction attempt if set to `complete'
                  or `correct' respectively; if set to `always', this will be
                  done for both cases.

          backslash_quote (+)
                  If set, backslashes (`\') always quote `\', `'', and `"'.
                  This may make complex quoting tasks easier, but it can cause
                  syntax errors in csh(1) scripts.

          catalog The file name of the message catalog.  If set, tcsh use
                  `tcsh.${catalog}' as a message catalog instead of default
                  `tcsh'.

          cdpath  A list of directories in which cd should search for
                  subdirectories if they aren't found in the current directory.

          color   If set, it enables color display for the builtin ls-F and it
                  passes --color=auto to ls.  Alternatively, it can be set to
                  only ls-F or only ls to enable color to only one command.
                  Setting it to nothing is equivalent to setting it to (ls-F
                  ls).

          colorcat
                  If set, it enables color escape sequence for NLS message
                  files.  And display colorful NLS messages.

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                                  14 February 2012

          command (+)
                  If set, the command which was passed to the shell with the -c
                  flag (q.v.).

          compat_expr (+)
                  If set, the shell will evaluate expressions right to left,
                  like the original csh.

          complete (+)
                  If set to `igncase', the completion becomes case insensitive.
                  If set to `enhance', completion ignores case and considers
                  hyphens and underscores to be equivalent; it will also treat
                  periods, hyphens and underscores (`.', `-' and `_') as word
                  separators.  If set to `Enhance', completion matches uppercase
                  and underscore characters explicitly and matches lowercase and
                  hyphens in a case-insensivite manner; it will treat periods,
                  hypens and underscores as word separators.

          continue (+)
                  If set to a list of commands, the shell will continue the
                  listed commands, instead of starting a new one.

          continue_args (+)
                  Same as continue, but the shell will execute:

                      echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

          correct (+)
                  If set to `cmd', commands are automatically spelling-
                  corrected.  If set to `complete', commands are automatically
                  completed.  If set to `all', the entire command line is
                  corrected.

          csubstnonl (+)
                  If set, newlines and carriage returns in command substitution
                  are replaced by spaces.  Set by default.

          cwd     The full pathname of the current directory.  See also the
                  dirstack and owd shell variables.

          dextract (+)
                  If set, `pushd +n' extracts the nth directory from the
                  directory stack rather than rotating it to the top.

          dirsfile (+)
                  The default location in which `dirs -S' and `dirs -L' look for
                  a history file.  If unset, ~/.cshdirs is used.  Because only
                  ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile
                  should be set in ~/.tcshrc rather than ~/.login.

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                                  14 February 2012

          dirstack (+)
                  An array of all the directories on the directory stack.
                  `$dirstack[1]' is the current working directory,
                  `$dirstack[2]' the first directory on the stack, etc.  Note
                  that the current working directory is `$dirstack[1]' but `=0'
                  in directory stack substitutions, etc.  One can change the
                  stack arbitrarily by setting dirstack, but the first element
                  (the current working directory) is always correct.  See also
                  the cwd and owd shell variables.

          dspmbyte (+)
                  Has an effect iff 'dspm' is listed as part of the version
                  shell variable.  If set to `euc', it enables display and
                  editing EUC-kanji(Japanese) code.  If set to `sjis', it
                  enables display and editing Shift-JIS(Japanese) code.  If set
                  to `big5', it enables display and editing Big5(Chinese) code.
                  If set to `utf8', it enables display and editing Utf8(Unicode)
                  code.  If set to the following format, it enables display and
                  editing of original multi-byte code format:

                      > set dspmbyte = 0000....(256 bytes)....0000

                  The table requires just 256 bytes.  Each character of 256
                  characters corresponds (from left to right) to the ASCII codes
                  0x00, 0x01, ... 0xff.  Each character is set to number 0,1,2
                  and 3.  Each number has the following meaning:
                    0 ... not used for multi-byte characters.
                    1 ... used for the first byte of a multi-byte character.
                    2 ... used for the second byte of a multi-byte character.
                    3 ... used for both the first byte and second byte of a
                  multi-byte character.

                    Example:
                  If set to `001322', the first character (means 0x00 of the
                  ASCII code) and second character (means 0x01 of ASCII code)
                  are set to `0'.  Then, it is not used for multi-byte
                  characters.  The 3rd character (0x02) is set to '1',
                  indicating that it is used for the first byte of a multi-byte
                  character.  The 4th character(0x03) is set '3'.  It is used
                  for both the first byte and the second byte of a multi-byte
                  character.  The 5th and 6th characters (0x04,0x05) are set to
                  '2', indicating that they are used for the second byte of a
                  multi-byte character.

                  The GNU fileutils version of ls cannot display multi-byte
                  filenames without the -N ( --literal ) option.   If you are
                  using this version, set the second word of dspmbyte to "ls".
                  If not, for example, "ls-F -l" cannot display multi-byte
                  filenames.

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                                  14 February 2012

                    Note:
                  This variable can only be used if KANJI and DSPMBYTE has been
                  defined at compile time.

          dunique (+)
                  If set, pushd removes any instances of name from the stack
                  before pushing it onto the stack.

          echo    If set, each command with its arguments is echoed just before
                  it is executed.  For non-builtin commands all expansions occur
                  before echoing.  Builtin commands are echoed before command
                  and filename substitution, because these substitutions are
                  then done selectively.  Set by the -x command line option.

          echo_style (+)
                  The style of the echo builtin.  May be set to

                  bsd     Don't echo a newline if the first argument is `-n'.
                  sysv    Recognize backslashed escape sequences in echo
                          strings.
                  both    Recognize both the `-n' flag and backslashed escape
                          sequences; the default.
                  none    Recognize neither.

                  Set by default to the local system default.  The BSD and
                  System V options are described in the echo(1) man pages on the
                  appropriate systems.

          edit (+)
                  If set, the command-line editor is used.  Set by default in
                  interactive shells.

          ellipsis (+)
                  If set, the `%c'/`%.' and `%C' prompt sequences (see the
                  prompt shell variable) indicate skipped directories with an
                  ellipsis (`...') instead of `/<skipped>'.

          euid (+)
                  The user's effective user ID.

          euser (+)
                  The first matching passwd entry name corresponding to the
                  effective user ID.

          fignore (+)
                  Lists file name suffixes to be ignored by completion.

          filec   In tcsh, completion is always used and this variable is
                  ignored by default. If edit is unset, then the traditional csh
                  completion is used.  If set in csh, filename completion is
                  used.

                                       - 64 -      Formatted:  February 27, 2012

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                                  14 February 2012

          gid (+) The user's real group ID.

          globdot (+)
                  If set, wild-card glob patterns will match files and
                  directories beginning with `.' except for `.' and `..'

          globstar (+)
                  If set, the `**' and `***' file glob patterns will match any
                  string of characters including `/' traversing any existing
                  sub-directories.  (e.g. `ls **.c' will list all the .c files
                  in the current directory tree).  If used by itself, it will
                  match match zero or more sub-directories (e.g. `ls
                  /usr/include/**/time.h' will list any file named `time.h' in
                  the /usr/include directory tree; whereas `ls
                  /usr/include/**time.h' will match any file in the /usr/include
                  directory tree ending in `time.h').  To prevent problems with
                  recursion, the `**' glob-pattern will not descend into a
                  symbolic link containing a directory.  To override this, use
                  `***'

          group (+)
                  The user's group name.

          highlight
                  If set, the incremental search match (in i-search-back and i-
                  search-fwd) and the region between the mark and the cursor are
                  highlighted in reverse video.

                  Highlighting requires more frequent terminal writes, which
                  introduces extra overhead. If you care about terminal
                  performance, you may want to leave this unset.

          histchars
                  A string value determining the characters used in History
                  substitution (q.v.).  The first character of its value is used
                  as the history substitution character, replacing the default
                  character `!'.  The second character of its value replaces the
                  character `^' in quick substitutions.

          histdup (+)
                  Controls handling of duplicate entries in the history list.
                  If set to `all' only unique history events are entered in the
                  history list.  If set to `prev' and the last history event is
                  the same as the current command, then the current command is
                  not entered in the history.  If set to `erase' and the same
                  event is found in the history list, that old event gets erased
                  and the current one gets inserted.  Note that the `prev' and
                  `all' options renumber history events so there are no gaps.

          histfile (+)
                  The default location in which `history -S' and `history -L'

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                                  14 February 2012

                  look for a history file.  If unset, ~/.history is used.
                  histfile is useful when sharing the same home directory
                  between different machines, or when saving separate histories
                  on different terminals.  Because only ~/.tcshrc is normally
                  sourced before ~/.history, histfile should be set in ~/.tcshrc
                  rather than ~/.login.

          histlit (+)
                  If set, builtin and editor commands and the savehist mechanism
                  use the literal (unexpanded) form of lines in the history
                  list.  See also the toggle-literal-history editor command.

          history The first word indicates the number of history events to save.
                  The optional second word (+) indicates the format in which
                  history is printed; if not given, `%h\t%T\t%R\n' is used.  The
                  format sequences are described below under prompt; note the
                  variable meaning of `%R'.  Set to `100' by default.

          home    Initialized to the home directory of the invoker.  The
                  filename expansion of `~' refers to this variable.

          ignoreeof
                  If set to the empty string or `0' and the input device is a
                  terminal, the end-of-file command (usually generated by the
                  user by typing `^D' on an empty line) causes the shell to
                  print `Use "exit" to leave tcsh.' instead of exiting.  This
                  prevents the shell from accidentally being killed.
                  Historically this setting exited after 26 successive EOF's to
                  avoid infinite loops.  If set to a number n, the shell ignores
                  n - 1 consecutive end-of-files and exits on the nth.  (+) If
                  unset, `1' is used, i.e., the shell exits on a single `^D'.

          implicitcd (+)
                  If set, the shell treats a directory name typed as a command
                  as though it were a request to change to that directory.  If
                  set to verbose, the change of directory is echoed to the
                  standard output.  This behavior is inhibited in non-
                  interactive shell scripts, or for command strings with more
                  than one word.  Changing directory takes precedence over
                  executing a like-named command, but it is done after alias
                  substitutions.  Tilde and variable expansions work as
                  expected.

          inputmode (+)
                  If set to `insert' or `overwrite', puts the editor into that
                  input mode at the beginning of each line.

          killdup (+)
                  Controls handling of duplicate entries in the kill ring.  If
                  set to `all' only unique strings are entered in the kill ring.
                  If set to `prev' and the last killed string is the same as the

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                                  14 February 2012

                  current killed string, then the current string is not entered
                  in the ring.  If set to `erase' and the same string is found
                  in the kill ring, the old string is erased and the current one
                  is inserted.

          killring (+)
                  Indicates the number of killed strings to keep in memory.  Set
                  to `30' by default.  If unset or set to less than `2', the
                  shell will only keep the most recently killed string.  Strings
                  are put in the killring by the editor commands that delete
                  (kill) strings of text, e.g. backward-delete-word, kill-line,
                  etc, as well as the copy-region-as-kill command.  The yank
                  editor command will yank the most recently killed string into
                  the command-line, while yank-pop (see Editor commands) can be
                  used to yank earlier killed strings.

          listflags (+)
                  If set to `x', `a' or `A', or any combination thereof (e.g.,
                  `xA'), they are used as flags to ls-F, making it act like `ls
                  -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'):
                  `a' shows all files (even if they start with a `.'), `A' shows
                  all files but `.' and `..', and `x' sorts across instead of
                  down.  If the second word of listflags is set, it is used as
                  the path to `ls(1)'.

          listjobs (+)
                  If set, all jobs are listed when a job is suspended.  If set
                  to `long', the listing is in long format.

          listlinks (+)
                  If set, the ls-F builtin command shows the type of file to
                  which each symbolic link points.

          listmax (+)
                  The maximum number of items which the list-choices editor
                  command will list without asking first.

          listmaxrows (+)
                  The maximum number of rows of items which the list-choices
                  editor command will list without asking first.

          loginsh (+)
                  Set by the shell if it is a login shell.  Setting or unsetting
                  it within a shell has no effect.  See also shlvl.

          logout (+)
                  Set by the shell to `normal' before a normal logout,
                  `automatic' before an automatic logout, and `hangup' if the
                  shell was killed by a hangup signal (see Signal handling).
                  See also the autologout shell variable.

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                                  14 February 2012

          mail    A list of files and directories to check for incoming mail,
                  optionally preceded by a numeric word.  Before each prompt, if
                  10 minutes have passed since the last check, the shell checks
                  each file and says `You have new mail.' (or, if mail contains
                  multiple files, `You have new mail in name.') if the filesize
                  is greater than zero in size and has a modification time
                  greater than its access time.

                  If you are in a login shell, then no mail file is reported
                  unless it has been modified after the time the shell has
                  started up, to prevent redundant notifications.  Most login
                  programs will tell you whether or not you have mail when you
                  log in.

                  If a file specified in mail is a directory, the shell will
                  count each file within that directory as a separate message,
                  and will report `You have n mails.' or `You have n mails in
                  name.' as appropriate.  This functionality is provided
                  primarily for those systems which store mail in this manner,
                  such as the Andrew Mail System.

                  If the first word of mail is numeric it is taken as a
                  different mail checking interval, in seconds.

                  Under very rare circumstances, the shell may report `You have
                  mail.' instead of `You have new mail.'

          matchbeep (+)
                  If set to `never', completion never beeps.  If set to
                  `nomatch', it beeps only when there is no match.  If set to
                  `ambiguous', it beeps when there are multiple matches.  If set
                  to `notunique', it beeps when there is one exact and other
                  longer matches.  If unset, `ambiguous' is used.

          nobeep (+)
                  If set, beeping is completely disabled.  See also visiblebell.

          noclobber
                  If set, restrictions are placed on output redirection to
                  insure that files are not accidentally destroyed and that `>>'
                  redirections refer to existing files, as described in the
                  Input/output section.

          noding  If set, disable the printing of `DING!' in the prompt time
                  specifiers at the change of hour.

          noglob  If set, Filename substitution and Directory stack substitution
                  (q.v.) are inhibited.  This is most useful in shell scripts
                  which do not deal with filenames, or after a list of filenames
                  has been obtained and further expansions are not desirable.

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                                  14 February 2012

          nokanji (+)
                  If set and the shell supports Kanji (see the version shell
                  variable), it is disabled so that the meta key can be used.

          nonomatch
                  If set, a Filename substitution or Directory stack
                  substitution (q.v.) which does not match any existing files is
                  left untouched rather than causing an error.  It is still an
                  error for the substitution to be malformed, e.g., `echo ['
                  still gives an error.

          nostat (+)
                  A list of directories (or glob-patterns which match
                  directories; see Filename substitution) that should not be
                  stat(2)ed during a completion operation.  This is usually used
                  to exclude directories which take too much time to stat(2),
                  for example /afs.

          notify  If set, the shell announces job completions asynchronously.
                  The default is to present job completions just before printing
                  a prompt.

          oid (+) The user's real organization ID.  (Domain/OS only)

          owd (+) The old working directory, equivalent to the `-' used by cd
                  and pushd.  See also the cwd and dirstack shell variables.

          padhour If set, enable the printing of padding '0' for hours, in 24
                  and 12 hour formats.  E.G.: 07:45:42 vs. 7:45:42.

          parseoctal
                  To retain compatibily with older versions numeric variables
                  starting with 0 are not interpreted as octal. Setting this
                  variable enables proper octal parsing.

          path    A list of directories in which to look for executable
                  commands.  A null word specifies the current directory.  If
                  there is no path variable then only full path names will
                  execute.  path is set by the shell at startup from the PATH
                  environment variable or, if PATH does not exist, to a system-
                  dependent default something like `(/usr/local/bin /usr/bsd
                  /bin /usr/bin .)'.  The shell may put `.' first or last in
                  path or omit it entirely depending on how it was compiled; see
                  the version shell variable.  A shell which is given neither
                  the -c nor the -t option hashes the contents of the
                  directories in path after reading ~/.tcshrc and each time path
                  is reset.  If one adds a new command to a directory in path
                  while the shell is active, one may need to do a rehash for the
                  shell to find it.

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                                  14 February 2012

          printexitvalue (+)
                  If set and an interactive program exits with a non-zero
                  status, the shell prints `Exit status'.

          prompt  The string which is printed before reading each command from
                  the terminal.  prompt may include any of the following
                  formatting sequences (+), which are replaced by the given
                  information:

                  %/  The current working directory.
                  %~  The current working directory, but with one's home
                      directory represented by `~' and other users' home
                      directories represented by `~user' as per Filename
                      substitution.  `~user' substitution happens only if the
                      shell has already used `~user' in a pathname in the
                      current session.
                  %c[[0]n], %.[[0]n]
                      The trailing component of the current working directory,
                      or n trailing components if a digit n is given.  If n
                      begins with `0', the number of skipped components precede
                      the trailing component(s) in the format
                      `/<skipped>trailing'.  If the ellipsis shell variable is
                      set, skipped components are represented by an ellipsis so
                      the whole becomes `...trailing'.  `~' substitution is done
                      as in `%~' above, but the `~' component is ignored when
                      counting trailing components.
                  %C  Like %c, but without `~' substitution.
                  %h, %!, !
                      The current history event number.
                  %M  The full hostname.
                  %m  The hostname up to the first `.'.
                  %S (%s)
                      Start (stop) standout mode.
                  %B (%b)
                      Start (stop) boldfacing mode.
                  %U (%u)
                      Start (stop) underline mode.
                  %t, %@
                      The time of day in 12-hour AM/PM format.
                  %T  Like `%t', but in 24-hour format (but see the ampm shell
                      variable).
                  %p  The `precise' time of day in 12-hour AM/PM format, with
                      seconds.
                  %P  Like `%p', but in 24-hour format (but see the ampm shell
                      variable).
                  \c  c is parsed as in bindkey.
                  ^c  c is parsed as in bindkey.
                  %%  A single `%'.
                  %n  The user name.
                  %N  The effective user name.

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                                  14 February 2012

                  %j  The number of jobs.
                  %d  The weekday in `Day' format.
                  %D  The day in `dd' format.
                  %w  The month in `Mon' format.
                  %W  The month in `mm' format.
                  %y  The year in `yy' format.
                  %Y  The year in `yyyy' format.
                  %l  The shell's tty.
                  %L  Clears from the end of the prompt to end of the display or
                      the end of the line.
                  %$  Expands the shell or environment variable name immediately
                      after the `$'.
                  %#  `>' (or the first character of the promptchars shell
                      variable) for normal users, `#' (or the second character
                      of promptchars) for the superuser.
                  %{string%}
                      Includes string as a literal escape sequence.  It should
                      be used only to change terminal attributes and should not
                      move the cursor location.  This cannot be the last
                      sequence in prompt.
                  %?  The return code of the command executed just before the
                      prompt.
                  %R  In prompt2, the status of the parser.  In prompt3, the
                      corrected string.  In history, the history string.

                  `%B', `%S', `%U' and `%{string%}' are available in only
                  eight-bit-clean shells; see the version shell variable.

                  The bold, standout and underline sequences are often used to
                  distinguish a superuser shell.  For example,

                      > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                      tut [37] [2:54pm] [/usr/accts/sys] you rang? _

                  If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
                  set, then print `DING!' on the change of hour (i.e, `:00'
                  minutes) instead of the actual time.

                  Set by default to `%# ' in interactive shells.

          prompt2 (+)
                  The string with which to prompt in while and foreach loops and
                  after lines ending in `\'.  The same format sequences may be
                  used as in prompt (q.v.); note the variable meaning of `%R'.
                  Set by default to `%R? ' in interactive shells.

          prompt3 (+)
                  The string with which to prompt when confirming automatic
                  spelling correction.  The same format sequences may be used as
                  in prompt (q.v.); note the variable meaning of `%R'.  Set by
                  default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

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                                  14 February 2012

          promptchars (+)
                  If set (to a two-character string), the `%#' formatting
                  sequence in the prompt shell variable is replaced with the
                  first character for normal users and the second character for
                  the superuser.

          pushdtohome (+)
                  If set, pushd without arguments does `pushd ~', like cd.

          pushdsilent (+)
                  If set, pushd and popd do not print the directory stack.

          recexact (+)
                  If set, completion completes on an exact match even if a
                  longer match is possible.

          recognize_only_executables (+)
                  If set, command listing displays only files in the path that
                  are executable.  Slow.

          rmstar (+)
                  If set, the user is prompted before `rm *' is executed.

          rprompt (+)
                  The string to print on the right-hand side of the screen
                  (after the command input) when the prompt is being displayed
                  on the left.  It recognizes the same formatting characters as
                  prompt.  It will automatically disappear and reappear as
                  necessary, to ensure that command input isn't obscured, and
                  will appear only if the prompt, command input, and itself will
                  fit together on the first line.  If edit isn't set, then
                  rprompt will be printed after the prompt and before the
                  command input.

          savedirs (+)
                  If set, the shell does `dirs -S' before exiting.  If the first
                  word is set to a number, at most that many directory stack
                  entries are saved.

          savehist
                  If set, the shell does `history -S' before exiting.  If the
                  first word is set to a number, at most that many lines are
                  saved.  (The number must be less than or equal to history.) If
                  the second word is set to `merge', the history list is merged
                  with the existing history file instead of replacing it (if
                  there is one) and sorted by time stamp and the most recent
                  events are retained.  (+)

          sched (+)
                  The format in which the sched builtin command prints scheduled
                  events; if not given, `%h\t%T\t%R\n' is used.  The format

                                       - 72 -      Formatted:  February 27, 2012

     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

                  sequences are described above under prompt; note the variable
                  meaning of `%R'.

          shell   The file in which the shell resides.  This is used in forking
                  shells to interpret files which have execute bits set, but
                  which are not executable by the system.  (See the description
                  of Builtin and non-builtin command execution.)  Initialized to
                  the (system-dependent) home of the shell.

          shlvl (+)
                  The number of nested shells.  Reset to 1 in login shells.  See
                  also loginsh.

          status  The status returned by the last command, unless the variable
                  anyerror is set, and any error in a pipeline or a backquote
                  expansion will be propagated (this is the default csh
                  behavior, and the current tcsh default). If it terminated
                  abnormally, then 0200 is added to the status.  Builtin
                  commands which fail return exit status `1', all other builtin
                  commands return status `0'.

          symlinks (+)
                  Can be set to several different values to control symbolic
                  link (`symlink') resolution:

                  If set to `chase', whenever the current directory changes to a
                  directory containing a symbolic link, it is expanded to the
                  real name of the directory to which the link points.  This
                  does not work for the user's home directory; this is a bug.

                  If set to `ignore', the shell tries to construct a current
                  directory relative to the current directory before the link
                  was crossed.  This means that cding through a symbolic link
                  and then `cd ..'ing returns one to the original directory.
                  This affects only builtin commands and filename completion.

                  If set to `expand', the shell tries to fix symbolic links by
                  actually expanding arguments which look like path names.  This
                  affects any command, not just builtins.  Unfortunately, this
                  does not work for hard-to-recognize filenames, such as those
                  embedded in command options.  Expansion may be prevented by
                  quoting.  While this setting is usually the most convenient,
                  it is sometimes misleading and sometimes confusing when it
                  fails to recognize an argument which should be expanded.  A
                  compromise is to use `ignore' and use the editor command
                  normalize-path (bound by default to ^X-n) when necessary.

                  Some examples are in order.  First, let's set up some play
                  directories:

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

                      > cd /tmp
                      > mkdir from from/src to
                      > ln -s from/src to/dst

                  Here's the behavior with symlinks unset,

                      > cd /tmp/to/dst; echo $cwd
                      /tmp/to/dst
                      > cd ..; echo $cwd
                      /tmp/from

                  here's the behavior with symlinks set to `chase',

                      > cd /tmp/to/dst; echo $cwd
                      /tmp/from/src
                      > cd ..; echo $cwd
                      /tmp/from

                  here's the behavior with symlinks set to `ignore',

                      > cd /tmp/to/dst; echo $cwd
                      /tmp/to/dst
                      > cd ..; echo $cwd
                      /tmp/to

                  and here's the behavior with symlinks set to `expand'.

                      > cd /tmp/to/dst; echo $cwd
                      /tmp/to/dst
                      > cd ..; echo $cwd
                      /tmp/to
                      > cd /tmp/to/dst; echo $cwd
                      /tmp/to/dst
                      > cd ".."; echo $cwd
                      /tmp/from
                      > /bin/echo ..
                      /tmp/to
                      > /bin/echo ".."
                      ..

                  Note that `expand' expansion 1) works just like `ignore' for
                  builtins like cd, 2) is prevented by quoting, and 3) happens
                  before filenames are passed to non-builtin commands.

          tcsh (+)
                  The version number of the shell in the format `R.VV.PP', where
                  `R' is the major release number, `VV' the current version and
                  `PP' the patchlevel.

          term    The terminal type.  Usually set in ~/.login as described under
                  Startup and shutdown.

                                       - 74 -      Formatted:  February 27, 2012

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                                  14 February 2012

          time    If set to a number, then the time builtin (q.v.) executes
                  automatically after each command which takes more than that
                  many CPU seconds.  If there is a second word, it is used as a
                  format string for the output of the time builtin.  (u) The
                  following sequences may be used in the format string:

                  %U  The time the process spent in user mode in cpu seconds.
                  %S  The time the process spent in kernel mode in cpu seconds.
                  %E  The elapsed (wall clock) time in seconds.
                  %P  The CPU percentage computed as (%U + %S) / %E.
                  %W  Number of times the process was swapped.
                  %X  The average amount in (shared) text space used in Kbytes.
                  %D  The average amount in (unshared) data/stack space used in
                      Kbytes.
                  %K  The total space used (%X + %D) in Kbytes.
                  %M  The maximum memory the process had in use at any time in
                      Kbytes.
                  %F  The number of major page faults (page needed to be brought
                      from disk).
                  %R  The number of minor page faults.
                  %I  The number of input operations.
                  %O  The number of output operations.
                  %r  The number of socket messages received.
                  %s  The number of socket messages sent.
                  %k  The number of signals received.
                  %w  The number of voluntary context switches (waits).
                  %c  The number of involuntary context switches.

                  Only the first four sequences are supported on systems without
                  BSD resource limit functions.  The default time format is `%Uu
                  %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support
                  resource usage reporting and `%Uu %Ss %E %P' for systems that
                  do not.

                  Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not
                  available, but the following additional sequences are:

                  %Y  The number of system calls performed.
                  %Z  The number of pages which are zero-filled on demand.
                  %i  The number of times a process's resident set size was
                      increased by the kernel.
                  %d  The number of times a process's resident set size was
                      decreased by the kernel.
                  %l  The number of read system calls performed.
                  %m  The number of write system calls performed.
                  %p  The number of reads from raw disk devices.
                  %q  The number of writes to raw disk devices.

                  and the default time format is `%Uu %Ss %E %P %I+%Oio
                  %Fpf+%Ww'.  Note that the CPU percentage can be higher than
                  100% on multi-processors.

                                       - 75 -      Formatted:  February 27, 2012

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                                  14 February 2012

          tperiod (+)
                  The period, in minutes, between executions of the periodic
                  special alias.

          tty (+) The name of the tty, or empty if not attached to one.

          uid (+) The user's real user ID.

          user    The user's login name.

          verbose If set, causes the words of each command to be printed, after
                  history substitution (if any).  Set by the -v command line
                  option.

          version (+)
                  The version ID stamp.  It contains the shell's version number
                  (see tcsh), origin, release date, vendor, operating system and
                  machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-
                  separated list of options which were set at compile time.
                  Options which are set by default in the distribution are
                  noted.

                  8b    The shell is eight bit clean; default
                  7b    The shell is not eight bit clean
                  wide  The shell is multibyte encoding clean (like UTF-8)
                  nls   The system's NLS is used; default for systems with NLS
                  lf    Login shells execute /etc/csh.login before instead of
                        after /etc/csh.cshrc and ~/.login before instead of
                        after ~/.tcshrc and ~/.history.
                  dl    `.' is put last in path for security; default
                  nd    `.' is omitted from path for security
                  vi    vi-style editing is the default rather than emacs
                  dtr   Login shells drop DTR when exiting
                  bye   bye is a synonym for logout and log is an alternate name
                        for watchlog
                  al    autologout is enabled; default
                  kan   Kanji is used if appropriate according to locale
                        settings, unless the nokanji shell variable is set
                  sm    The system's malloc(3) is used
                  hb    The `#!<program> <args>' convention is emulated when
                        executing shell scripts
                  ng    The newgrp builtin is available
                  rh    The shell attempts to set the REMOTEHOST environment
                        variable
                  afs   The shell verifies your password with the kerberos
                        server if local authentication fails.  The afsuser shell
                        variable or the AFSUSER environment variable override
                        your local username if set.

                  An administrator may enter additional strings to indicate
                  differences in the local version.

                                       - 76 -      Formatted:  February 27, 2012

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                                  14 February 2012

          visiblebell (+)
                  If set, a screen flash is used rather than the audible bell.
                  See also nobeep.

          watch (+)
                  A list of user/terminal pairs to watch for logins and logouts.
                  If either the user is `any' all terminals are watched for the
                  given user and vice versa.  Setting watch to `(any any)'
                  watches all users and terminals.  For example,

                      set watch = (george ttyd1 any console $user any)

                  reports activity of the user `george' on ttyd1, any user on
                  the console, and oneself (or a trespasser) on any terminal.

                  Logins and logouts are checked every 10 minutes by default,
                  but the first word of watch can be set to a number to check
                  every so many minutes.  For example,

                      set watch = (1 any any)

                  reports any login/logout once every minute.  For the
                  impatient, the log builtin command triggers a watch report at
                  any time.  All current logins are reported (as with the log
                  builtin) when watch is first set.

                  The who shell variable controls the format of watch reports.

          who (+) The format string for watch messages.  The following sequences
                  are replaced by the given information:

                  %n  The name of the user who logged in/out.
                  %a  The observed action, i.e., `logged on', `logged off' or
                      `replaced olduser on'.
                  %l  The terminal (tty) on which the user logged in/out.
                  %M  The full hostname of the remote host, or `local' if the
                      login/logout was from the local host.
                  %m  The hostname of the remote host up to the first `.'.  The
                      full name is printed if it is an IP address or an X Window
                      System display.

                  %M and %m are available on only systems that store the remote
                  hostname in /etc/utmp.  If unset, `%n has %a %l from %m.' is
                  used, or `%n has %a %l.' on systems which don't store the
                  remote hostname.

          wordchars (+)
                  A list of non-alphanumeric characters to be considered part of
                  a word by the forward-word, backward-word etc., editor
                  commands.  If unset, `*?_-.[]~=' is used.

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

     ENVIRONMENT
          AFSUSER (+)
                  Equivalent to the afsuser shell variable.

          COLUMNS The number of columns in the terminal.  See Terminal
                  management.

          DISPLAY Used by X Window System (see X(1)).  If set, the shell does
                  not set autologout (q.v.).

          EDITOR  The pathname to a default editor.  See also the VISUAL
                  environment variable and the run-fg-editor editor command.

          GROUP (+)
                  Equivalent to the group shell variable.

          HOME    Equivalent to the home shell variable.

          HOST (+)
                  Initialized to the name of the machine on which the shell is
                  running, as determined by the gethostname(2) system call.

          HOSTTYPE (+)
                  Initialized to the type of machine on which the shell is
                  running, as determined at compile time.  This variable is
                  obsolete and will be removed in a future version.

          HPATH (+)
                  A colon-separated list of directories in which the run-help
                  editor command looks for command documentation.

          LANG    Gives the preferred character environment.  See Native
                  Language System support.

          LC_CTYPE
                  If set, only ctype character handling is changed.  See Native
                  Language System support.

          LINES   The number of lines in the terminal.  See Terminal management.

          LS_COLORS
                  The format of this variable is reminiscent of the termcap(5)
                  file format; a colon-separated list of expressions of the form
                  "xx=string", where "xx" is a two-character variable name.  The
                  variables with their associated defaults are:

                      no   0      Normal (non-filename) text
                      fi   0      Regular file
                      di   01;34  Directory
                      ln   01;36  Symbolic link

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

                      pi   33     Named pipe (FIFO)
                      so   01;35  Socket
                      do   01;35  Door
                      bd   01;33  Block device
                      cd   01;32  Character device
                      ex   01;32  Executable file
                      mi   (none) Missing file (defaults to fi)
                      or   (none) Orphaned symbolic link (defaults to ln)
                      lc   ^[[    Left code
                      rc   m      Right code
                      ec   (none) End code (replaces lc+no+rc)

                  You need to include only the variables you want to change from
                  the default.

                  File names can also be colorized based on filename extension.
                  This is specified in the LS_COLORS variable using the syntax
                  "*ext=string".  For example, using ISO 6429 codes, to color
                  all C-language source files blue you would specify "*.c=34".
                  This would color all files ending in .c in blue (34) color.

                  Control characters can be written either in C-style-escaped
                  notation, or in stty-like ^-notation.  The C-style notation
                  adds ^[ for Escape, _ for a normal space character, and ? for
                  Delete.  In addition, the ^[ escape character can be used to
                  override the default interpretation of ^[, ^, : and =.

                  Each file will be written as <lc> <color-code> <rc> <filename>
                  <ec>.  If the <ec> code is undefined, the sequence <lc> <no>
                  <rc> will be used instead.  This is generally more convenient
                  to use, but less general.  The left, right and end codes are
                  provided so you don't have to type common parts over and over
                  again and to support weird terminals; you will generally not
                  need to change them at all unless your terminal does not use
                  ISO 6429 color sequences but a different system.

                  If your terminal does use ISO 6429 color codes, you can
                  compose the type codes (i.e., all except the lc, rc, and ec
                  codes) from numerical commands separated by semicolons.  The
                  most common commands are:

                          0   to restore default color
                          1   for brighter colors
                          4   for underlined text
                          5   for flashing text
                          30  for black foreground
                          31  for red foreground
                          32  for green foreground
                          33  for yellow (or brown) foreground
                          34  for blue foreground

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

                          35  for purple foreground
                          36  for cyan foreground
                          37  for white (or gray) foreground
                          40  for black background
                          41  for red background
                          42  for green background
                          43  for yellow (or brown) background
                          44  for blue background
                          45  for purple background
                          46  for cyan background
                          47  for white (or gray) background

                  Not all commands will work on all systems or display devices.

                  A few terminal programs do not recognize the default end code
                  properly.  If all text gets colorized after you do a directory
                  listing, try changing the no and fi codes from 0 to the
                  numerical codes for your standard fore- and background colors.

          MACHTYPE (+)
                  The machine type (microprocessor class or machine model), as
                  determined at compile time.

          NOREBIND (+)
                  If set, printable characters are not rebound to self-insert-
                  command.  See Native Language System support.

          OSTYPE (+)
                  The operating system, as determined at compile time.

          PATH    A colon-separated list of directories in which to look for
                  executables.  Equivalent to the path shell variable, but in a
                  different format.

          PWD (+) Equivalent to the cwd shell variable, but not synchronized to
                  it; updated only after an actual directory change.

          REMOTEHOST (+)
                  The host from which the user has logged in remotely, if this
                  is the case and the shell is able to determine it.  Set only
                  if the shell was so compiled; see the version shell variable.

          SHLVL (+)
                  Equivalent to the shlvl shell variable.

          SYSTYPE (+)
                  The current system type.  (Domain/OS only)

          TERM    Equivalent to the term shell variable.

                                       - 80 -      Formatted:  February 27, 2012

     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

          TERMCAP The terminal capability string.  See Terminal management.

          USER    Equivalent to the user shell variable.

          VENDOR (+)
                  The vendor, as determined at compile time.

          VISUAL  The pathname to a default full-screen editor.  See also the
                  EDITOR environment variable and the run-fg-editor editor
                  command.

     FILES
          /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and
                          Intel use /etc/cshrc and NeXTs use /etc/cshrc.std.
                          A/UX, AMIX, Cray and IRIX have no equivalent in
                          csh(1), but read this file in tcsh anyway.  Solaris
                          2.x does not have it either, but tcsh reads
                          /etc/.cshrc.  (+)
          /etc/csh.login  Read by login shells after /etc/csh.cshrc.  ConvexOS,
                          Stellix and Intel use /etc/login, NeXTs use
                          /etc/login.std, Solaris 2.x uses /etc/.login and A/UX,
                          AMIX, Cray and IRIX use /etc/cshrc.
          ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its
                          equivalent.
          ~/.cshrc        Read by every shell, if ~/.tcshrc doesn't exist, after
                          /etc/csh.cshrc or its equivalent.  This manual uses
                          `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
                          found, ~/.cshrc'.
          ~/.history      Read by login shells after ~/.tcshrc if savehist is
                          set, but see also histfile.
          ~/.login        Read by login shells after ~/.tcshrc or ~/.history.
                          The shell may be compiled to read ~/.login before
                          instead of after ~/.tcshrc and ~/.history; see the
                          version shell variable.
          ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is
                          set, but see also dirsfile.
          /etc/csh.logout Read by login shells at logout.  ConvexOS, Stellix and
                          Intel use /etc/logout and NeXTs use /etc/logout.std.
                          A/UX, AMIX, Cray and IRIX have no equivalent in
                          csh(1), but read this file in tcsh anyway.  Solaris
                          2.x does not have it either, but tcsh reads
                          /etc/.logout.  (+)
          ~/.logout       Read by login shells at logout after /etc/csh.logout
                          or its equivalent.
          /bin/sh         Used to interpret shell scripts not starting with a
                          `#'.
          /tmp/sh*        Temporary file for `<<'.
          /etc/passwd     Source of home directories for `~name' substitutions.

          The order in which startup files are read may differ if the shell was
          so compiled; see Startup and shutdown and the version shell variable.

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                                  14 February 2012

     NEW FEATURES (+)
          This manual describes tcsh as a single entity, but experienced csh(1)
          users will want to pay special attention to tcsh's new features.

          A command-line editor, which supports GNU Emacs or vi(1)-style key
          bindings.  See The command-line editor and Editor commands.

          Programmable, interactive word completion and listing.  See Completion
          and listing and the complete and uncomplete builtin commands.

          Spelling correction (q.v.) of filenames, commands and variables.

          Editor commands (q.v.) which perform other useful functions in the
          middle of typed commands, including documentation lookup (run-help),
          quick editor restarting (run-fg-editor) and command resolution
          (which-command).

          An enhanced history mechanism.  Events in the history list are time-
          stamped.  See also the history command and its associated shell
          variables, the previously undocumented `#' event specifier and new
          modifiers under History substitution, the *-history, history-search-*,
          i-search-*, vi-search-* and toggle-literal-history editor commands and
          the histlit shell variable.

          Enhanced directory parsing and directory stack handling.  See the cd,
          pushd, popd and dirs commands and their associated shell variables,
          the description of Directory stack substitution, the dirstack, owd and
          symlinks shell variables and the normalize-command and normalize-path
          editor commands.

          Negation in glob-patterns.  See Filename substitution.

          New File inquiry operators (q.v.) and a filetest builtin which uses
          them.

          A variety of Automatic, periodic and timed events (q.v.) including
          scheduled events, special aliases, automatic logout and terminal
          locking, command timing and watching for logins and logouts.

          Support for the Native Language System (see Native Language System
          support), OS variant features (see OS variant support and the
          echo_style shell variable) and system-dependent file locations (see
          FILES).

          Extensive terminal-management capabilities.  See Terminal management.

          New builtin commands including builtins, hup, ls-F, newgrp, printenv,
          which and where (q.v.).

          New variables that make useful information easily available to the
          shell.  See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

          shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
          environment variables.

          A new syntax for including useful information in the prompt string
          (see prompt), and special prompts for loops and spelling correction
          (see prompt2 and prompt3).

          Read-only variables.  See Variable substitution.

     BUGS
          When a suspended command is restarted, the shell prints the directory
          it started in if this is different from the current directory.  This
          can be misleading (i.e., wrong) as the job may have changed
          directories internally.

          Shell builtin functions are not stoppable/restartable.  Command
          sequences of the form `a ; b ; c' are also not handled gracefully when
          stopping is attempted.  If you suspend `b', the shell will then
          immediately execute `c'.  This is especially noticeable if this
          expansion results from an alias.  It suffices to place the sequence of
          commands in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.

          Control over tty output after processes are started is primitive;
          perhaps this will inspire someone to work on a good virtual terminal
          interface.  In a virtual terminal interface much more interesting
          things could be done with output control.

          Alias substitution is most often used to clumsily simulate shell
          procedures; shell procedures should be provided rather than aliases.

          Control structures should be parsed rather than being recognized as
          built-in commands.  This would allow control commands to be placed
          anywhere, to be combined with `|', and to be used with `&' and `;'
          metasyntax.

          foreach doesn't ignore here documents when looking for its end.

          It should be possible to use the `:' modifiers on the output of
          command substitutions.

          The screen update for lines longer than the screen width is very poor
          if the terminal cannot move the cursor up (i.e., terminal type
          `dumb').

          HPATH and NOREBIND don't need to be environment variables.

          Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or
          `~' are not negated correctly.

          The single-command form of if does output redirection even if the
          expression is false and the command is not executed.

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

          ls-F includes file identification characters when sorting filenames
          and does not handle control characters in filenames well.  It cannot
          be interrupted.

          Command substitution supports multiple commands and conditions, but
          not cycles or backward gotos.

          Report bugs at http://bugs.gw.com/, preferably with fixes.  If you
          want to help maintain and test tcsh, send mail to tcsh-
          request@mx.gw.com with the text `subscribe tcsh' on a line by itself
          in the body.

     THE T IN TCSH
          In 1964, DEC produced the PDP-6.  The PDP-10 was a later re-
          implementation.  It was re-christened the DECsystem-10 in 1970 or so
          when DEC brought out the second model, the KI10.

          TENEX was created at Bolt, Beranek & Newman (a Cambridge,
          Massachusetts think tank) in 1972 as an experiment in demand-paged
          virtual memory operating systems.  They built a new pager for the DEC
          PDP-10 and created the OS to go with it.  It was extremely successful
          in academia.

          In 1975, DEC brought out a new model of the PDP-10, the KL10; they
          intended to have only a version of TENEX, which they had licensed from
          BBN, for the new box.  They called their version TOPS-20 (their
          capitalization is trademarked).  A lot of TOPS-10 users (`The
          OPerating System for PDP-10') objected; thus DEC found themselves
          supporting two incompatible systems on the same hardware--but then
          there were 6 on the PDP-11!

          TENEX, and TOPS-20 to version 3, had command completion via a user-
          code-level subroutine library called ULTCMD.  With version 3, DEC
          moved all that capability and more into the monitor (`kernel' for you
          Unix types), accessed by the COMND% JSYS (`Jump to SYStem'
          instruction, the supervisor call mechanism [are my IBM roots also
          showing?]).

          The creator of tcsh was impressed by this feature and several others
          of TENEX and TOPS-20, and created a version of csh which mimicked
          them.

     LIMITATIONS
          The system limits argument lists to ARG_MAX characters.

          The number of arguments to a command which involves filename expansion
          is limited to 1/6th the number of characters allowed in an argument
          list.

          Command substitutions may substitute no more characters than are
          allowed in an argument list.

                                       - 84 -      Formatted:  February 27, 2012

     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

          To detect looping, the shell restricts the number of alias
          substitutions on a single line to 20.

     SEE ALSO
          csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
          tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2),
          pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2),
          wait(2), malloc(3), setlocale(3), tty(4), a.out(5), termcap(5),
          environ(7), termio(7), Introduction to the C Shell

     VERSION
          This manual documents tcsh 6.18.01 (Astron) 2012-02-14.

     AUTHORS
          William Joy
            Original author of csh(1)
          J.E. Kulp, IIASA, Laxenburg, Austria
            Job control and directory stack features
          Ken Greer, HP Labs, 1981
            File name completion
          Mike Ellis, Fairchild, 1983
            Command name recognition/completion
          Paul Placeway, Ohio State CIS Dept., 1983-1993
            Command line editor, prompt routines, new glob syntax and numerous
            fixes and speedups
          Karl Kleinpaste, CCI 1983-4
            Special aliases, directory stack extraction stuff, login/logout
            watch, scheduled events, and the idea of the new prompt format
          Rayan Zachariassen, University of Toronto, 1984
            ls-F and which builtins and numerous bug fixes, modifications and
            speedups
          Chris Kingsley, Caltech
            Fast storage allocator routines
          Chris Grevstad, TRW, 1987
            Incorporated 4.3BSD csh into tcsh
          Christos S. Zoulas, Cornell U. EE Dept., 1987-94
            Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,
            SHORT_STRINGS support and a new version of sh.glob.c
          James J Dempsey, BBN, and Paul Placeway, OSU, 1988
            A/UX port
          Daniel Long, NNSC, 1988
            wordchars
          Patrick Wolfe, Kuck and Associates, Inc., 1988
            vi mode cleanup
          David C Lawrence, Rensselaer Polytechnic Institute, 1989
            autolist and ambiguous completion listing
          Alec Wolman, DEC, 1989
            Newlines in the prompt
          Matt Landau, BBN, 1989
            ~/.tcshrc

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     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

          Ray Moody, Purdue Physics, 1989
            Magic space bar history expansion
          Mordechai ????, Intel, 1989
            printprompt() fixes and additions
          Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
            Automatic spelling correction and prompt3
          Per Hedeland, Ellemtel, Sweden, 1990-
            Various bugfixes, improvements and manual updates
          Hans J. Albertsson (Sun Sweden)
            ampm, settc and telltc
          Michael Bloom
            Interrupt handling fixes
          Michael Fine, Digital Equipment Corp
            Extended key support
          Eric Schnoebelen, Convex, 1990
            Convex support, lots of csh bug fixes, save and restore of directory
            stack
          Ron Flax, Apple, 1990
            A/UX 2.0 (re)port
          Dan Oscarsson, LTH Sweden, 1990
            NLS support and simulated NLS support for non NLS sites, fixes
          Johan Widen, SICS Sweden, 1990
            shlvl, Mach support, correct-line, 8-bit printing
          Matt Day, Sanyo Icon, 1990
            POSIX termio support, SysV limit fixes
          Jaap Vermeulen, Sequent, 1990-91
            Vi mode fixes, expand-line, window change fixes, Symmetry port
          Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
            autolist beeping options, modified the history search to search for
            the whole string from the beginning of the line to the cursor.
          Scott Krotz, Motorola, 1991
            Minix port
          David Dawes, Sydney U. Australia, Physics Dept., 1991
            SVR4 job control fixes
          Jose Sousa, Interactive Systems Corp., 1991
            Extended vi fixes and vi delete command
          Marc Horowitz, MIT, 1991
            ANSIfication fixes, new exec hashing code, imake fixes, where
          Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
            ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
            and various other portability changes and bug fixes
          Jeff Fink, 1992
            complete-word-fwd and complete-word-back
          Harry C. Pulley, 1992
            Coherent port
          Andy Phillips, Mullard Space Science Lab U.K., 1992
            VMS-POSIX port
          Beto Appleton, IBM Corp., 1992
            Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
            SIGHUP

                                       - 86 -      Formatted:  February 27, 2012

     TCSH(1)                       Astron 6.18.01                        TCSH(1)
                                  14 February 2012

          Scott Bolte, Cray Computer Corp., 1992
            CSOS port
          Kaveh R. Ghazi, Rutgers University, 1992
            Tek, m88k, Titan and Masscomp ports and fixes.  Added autoconf
            support.
          Mark Linderman, Cornell University, 1992
            OS/2 port
          Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
            Linux port
          Tim P. Starrin, NASA Langley Research Center Operations, 1993
            Read-only variables
          Dave Schweisguth, Yale University, 1993-4
            New man page and tcsh.man2html
          Larry Schwimmer, Stanford University, 1993
            AFS and HESIOD patches
          Luke Mewburn, RMIT University, 1994-6
            Enhanced directory printing in prompt, added ellipsis and rprompt.
          Edward Hutchins, Silicon Graphics Inc., 1996
            Added implicit cd.
          Martin Kraemer, 1997
            Ported to Siemens Nixdorf EBCDIC machine
          Amol Deshpande, Microsoft, 1997
            Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
            library and message catalog code to interface to Windows.
          Taga Nayuta, 1998
            Color ls additions.

     THANKS TO
          Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve
          Romig, Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky
          and all the other people at Ohio State for suggestions and
          encouragement

          All the people on the net, for putting up with, reporting bugs in, and
          suggesting new additions to each and every version

          Richard M. Alderson III, for writing the `T in tcsh' section

                                       - 87 -      Formatted:  February 27, 2012