# Programming Ruby ### The Pragmatic Programmer's Guide
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module FileTest

### Index:

blockdev? chardev? directory? executable? executable_real? exist? exists? file? grpowned? owned? pipe? readable? readable_real? setgid? setuid? size size? socket? sticky? symlink? writable? writable_real? zero?

`FileTest` implements file test operations similar to those used in `File::Stat`.

instance methods
blockdev? | FileTest.blockdev?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is a block device, `false` if it isn't or if the operating system doesn't support this feature.
`FileTest.blockdev?( "testfile" )` | » | `false`
chardev? | FileTest.chardev?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is a character device, `false` if it isn't or if the operating system doesn't support this feature.
`FileTest.chardev?( "/dev/tty" )` | » | `true`
directory? | FileTest.directory?( aString ) -> `true` or `false`
|  | Returns `true` if this named file is a directory, `false` otherwise.
`FileTest.directory?( "." )` | » | `true`
executable? | FileTest.executable?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is executable. The tests are made using the effective owner of the process.
`FileTest.executable?( "testfile" )` | » | `false`
executable_real? | FileTest.executable_real?( aString ) -> `true` or `false`
|  | Same as `FileTest#executable?` , but tests using the real owner of the process.
exist? | FileTest.exist? ( aString ) -> `true` or `false`
|  | Returns `true` if the named file exists.
`FileTest.exist?( "testfile" )` | » | `true`
exists? | FileTest.exists? ( aString ) -> `true` or `false`
|  | Synonym for `FileTest::exist?` .
file? | FileTest.file?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is a regular file (not a device file, pipe, socket, etc.).
`FileTest.file?( "testfile" )` | » | `true`
grpowned? | FileTest.grpowned?( aString ) -> `true` or `false`
|  | Returns `true` if the effective group id of the process is the same as the group id of the named file. On Windows NT, returns `false`.
`FileTest.grpowned?( "/etc/passwd" )` | » | `false`
owned? | FileTest.owned?( aString ) -> `true` or `false`
|  | Returns `true` if the effective user id of the process is the same as the owner of the named file.
`FileTest.owned?( "/etc/passwd" )` | » | `false`
pipe? | FileTest.pipe?( aString ) -> `true` or `false`
|  | Returns `true` if the operating system supports pipes and the named file is a pipe, `false` otherwise.
`FileTest.pipe?( "testfile" )` | » | `false`
readable? | FileTest.readable?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is readable by the effective user id of this process.
`FileTest.readable?( "testfile" )` | » | `true`
readable_real? | FileTest.readable_real?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is readable by the real user id of this process.
`FileTest.readable_real?( "testfile" )` | » | `true`
setgid? | FileTest.setgid?( aString ) -> `true` or `false`
|  | Returns `true` if the named file's set-group-id permission bit is set, and `false` if it isn't or if the operating system doesn't support this feature.
`FileTest.setgid?( "/usr/sbin/lpc" )` | » | `true`
setuid? | FileTest.setuid?( aString ) -> `true` or `false`
|  | Returns `true` if the named file's set-user-id permission bit is set, and `false` if it isn't or if the operating system doesn't support this feature.
`FileTest.setuid?( "/bin/su" )` | » | `true`
size | FileTest.size( aString ) -> anInteger
|  | Returns the size of the named file in bytes.
`FileTest.size( "testfile" )` | » | `66`
size? | FileTest.size?( aString ) -> aFixnum or `nil`
|  | Returns `nil` if the named file is of zero length; otherwise, returns a nonzero aFixnum.
`FileTest.size?( "testfile" )` | » | `66`
`FileTest.size?( "/dev/zero" )` | » | `nil`
socket? | FileTest.socket?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is a socket, `false` if it isn't or if the operating system doesn't support this feature.
sticky? | FileTest.sticky?( aString ) -> `true` or `false`
|  | Returns `true` if the named file has its sticky bit set, `false` if it doesn't or if the operating system doesn't support this feature.
symlink? | FileTest.symlink?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is a symbolic link, `false` if it isn't or if the operating system doesn't support this feature.
writable? | FileTest.writable?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is writable by the effective user id of this process.
writable_real? | FileTest.writable_real?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is writable by the real user id of this process.
zero? | FileTest.zero?( aString ) -> `true` or `false`
|  | Returns `true` if the named file is of zero length, `false` otherwise.

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Extracted from the book "Programming Ruby - The Pragmatic Programmer's Guide"
Copyright © 2001 by Addison Wesley Longman, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/)).

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