File::Spec
File::Spec(3) User Contributed Perl Documentation File::Spec(3)
NAME
File::Spec - portably perform operations on file names
SYNOPSIS
use File::Spec;
$x=File::Spec->catfile('a', 'b', 'c');
which returns 'a/b/c' under Unix. Or:
use File::Spec::Functions;
$x = catfile('a', 'b', 'c');
DESCRIPTION
This module is designed to support operations commonly performed on
file specifications (usually called "file names", but not to be con-
fused with the contents of a file, or Perl's file handles), such as
concatenating several directory and file names into a single path, or
determining whether a path is rooted. It is based on code directly
taken from MakeMaker 5.17, code written by Andreas Koenig, Andy
Dougherty, Charles Bailey, Ilya Zakharevich, Paul Schinder, and others.
Since these functions are different for most operating systems, each
set of OS specific routines is available in a separate module, includ-
ing:
File::Spec::Unix
File::Spec::Mac
File::Spec::OS2
File::Spec::Win32
File::Spec::VMS
The module appropriate for the current OS is automatically loaded by
File::Spec. Since some modules (like VMS) make use of facilities avail-
able only under that OS, it may not be possible to load all modules
under all operating systems.
Since File::Spec is object oriented, subroutines should not be called
directly, as in:
File::Spec::catfile('a','b');
but rather as class methods:
File::Spec->catfile('a','b');
For simple uses, File::Spec::Functions provides convenient functional
forms of these methods.
METHODS
canonpath
No physical check on the filesystem, but a logical cleanup of a path.
$cpath = File::Spec->canonpath( $path ) ;
Note that this does *not* collapse x/../y sections into y. This is
by design. If /foo on your system is a symlink to /bar/baz, then
/foo/../quux is actually /bar/quux, not /quux as a naive ../-removal
would give you. If you want to do this kind of processing, you prob-
ably want "Cwd"'s "realpath()" function to actually traverse the
filesystem cleaning up paths like this.
catdir
Concatenate two or more directory names to form a complete path end-
ing with a directory. But remove the trailing slash from the result-
ing string, because it doesn't look good, isn't necessary and con-
fuses OS/2. Of course, if this is the root directory, don't cut off
the trailing slash :-)
$path = File::Spec->catdir( @directories );
catfile
Concatenate one or more directory names and a filename to form a com-
plete path ending with a filename
$path = File::Spec->catfile( @directories, $filename );
curdir
Returns a string representation of the current directory.
$curdir = File::Spec->curdir();
devnull
Returns a string representation of the null device.
$devnull = File::Spec->devnull();
rootdir
Returns a string representation of the root directory.
$rootdir = File::Spec->rootdir();
tmpdir
Returns a string representation of the first writable directory from
a list of possible temporary directories. Returns the current direc-
tory if no writable temporary directories are found. The list of
directories checked depends on the platform; e.g. File::Spec::Unix
checks $ENV{TMPDIR} (unless taint is on) and /tmp.
$tmpdir = File::Spec->tmpdir();
updir
Returns a string representation of the parent directory.
$updir = File::Spec->updir();
no_upwards
Given a list of file names, strip out those that refer to a parent
directory. (Does not strip symlinks, only '.', '..', and equiva-
lents.)
@paths = File::Spec->no_upwards( @paths );
case_tolerant
Returns a true or false value indicating, respectively, that alpha-
betic case is not or is significant when comparing file specifica-
tions.
$is_case_tolerant = File::Spec->case_tolerant();
file_name_is_absolute
Takes as its argument a path, and returns true if it is an absolute
path.
$is_absolute = File::Spec->file_name_is_absolute( $path );
This does not consult the local filesystem on Unix, Win32, OS/2, or
Mac OS (Classic). It does consult the working environment for VMS
(see "file_name_is_absolute" in File::Spec::VMS).
path
Takes no argument. Returns the environment variable "PATH" (or the
local platform's equivalent) as a list.
@PATH = File::Spec->path();
join
join is the same as catfile.
splitpath
Splits a path in to volume, directory, and filename portions. On sys-
tems with no concept of volume, returns '' for volume.
($volume,$directories,$file) = File::Spec->splitpath( $path );
($volume,$directories,$file) = File::Spec->splitpath( $path, $no_file );
For systems with no syntax differentiating filenames from directo-
ries, assumes that the last file is a path unless $no_file is true or
a trailing separator or /. or /.. is present. On Unix, this means
that $no_file true makes this return ( '', $path, '' ).
The directory portion may or may not be returned with a trailing '/'.
The results can be passed to "catpath()" to get back a path equiva-
lent to (usually identical to) the original path.
splitdir
The opposite of "catdir()".
@dirs = File::Spec->splitdir( $directories );
$directories must be only the directory portion of the path on sys-
tems that have the concept of a volume or that have path syntax that
differentiates files from directories.
Unlike just splitting the directories on the separator, empty direc-
tory names ('') can be returned, because these are significant on
some OSes.
catpath()
Takes volume, directory and file portions and returns an entire path.
Under Unix, $volume is ignored, and directory and file are concate-
nated. A '/' is inserted if need be. On other OSes, $volume is sig-
nificant.
$full_path = File::Spec->catpath( $volume, $directory, $file );
abs2rel
Takes a destination path and an optional base path returns a relative
path from the base path to the destination path:
$rel_path = File::Spec->abs2rel( $path ) ;
$rel_path = File::Spec->abs2rel( $path, $base ) ;
If $base is not present or '', then Cwd::cwd() is used. If $base is
relative, then it is converted to absolute form using "rel2abs()".
This means that it is taken to be relative to Cwd::cwd().
On systems with the concept of volume, if $path and $base appear to
be on two different volumes, we will not attempt to resolve the two
paths, and we will instead simply return $path. Note that previous
versions of this module ignored the volume of $base, which resulted
in garbage results part of the time.
On systems that have a grammar that indicates filenames, this ignores
the $base filename as well. Otherwise all path components are assumed
to be directories.
If $path is relative, it is converted to absolute form using
"rel2abs()". This means that it is taken to be relative to
Cwd::cwd().
No checks against the filesystem are made. On VMS, there is interac-
tion with the working environment, as logicals and macros are
expanded.
Based on code written by Shigio Yamaguchi.
rel2abs()
Converts a relative path to an absolute path.
$abs_path = File::Spec->rel2abs( $path ) ;
$abs_path = File::Spec->rel2abs( $path, $base ) ;
If $base is not present or '', then Cwd::cwd() is used. If $base is
relative, then it is converted to absolute form using "rel2abs()".
This means that it is taken to be relative to Cwd::cwd().
On systems with the concept of volume, if $path and $base appear to
be on two different volumes, we will not attempt to resolve the two
paths, and we will instead simply return $path. Note that previous
versions of this module ignored the volume of $base, which resulted
in garbage results part of the time.
On systems that have a grammar that indicates filenames, this ignores
the $base filename as well. Otherwise all path components are assumed
to be directories.
If $path is absolute, it is cleaned up and returned using "canon-
path()".
No checks against the filesystem are made. On VMS, there is interac-
tion with the working environment, as logicals and macros are
expanded.
Based on code written by Shigio Yamaguchi.
For further information, please see File::Spec::Unix, File::Spec::Mac,
File::Spec::OS2, File::Spec::Win32, or File::Spec::VMS.
SEE ALSO
File::Spec::Unix, File::Spec::Mac, File::Spec::OS2, File::Spec::Win32,
File::Spec::VMS, File::Spec::Functions, ExtUtils::MakeMaker
AUTHOR
Currently maintained by Ken Williams "<KWILLIAMS@cpan.org>".
The vast majority of the code was written by Kenneth Albanowski
"<kjahds@kjahds.com>", Andy Dougherty "<doughera@lafayette.edu>",
Andreas Koenig "<A.Koenig@franz.ww.TU-Berlin.DE>", Tim Bunce
"<Tim.Bunce@ig.co.uk>". VMS support by Charles Bailey "<bailey@new-
man.upenn.edu>". OS/2 support by Ilya Zakharevich
"<ilya@math.ohio-state.edu>". Mac support by Paul Schinder "<schin-
der@pobox.com>", and Thomas Wegner "<wegner_thomas@yahoo.com>".
abs2rel() and rel2abs() written by Shigio Yamaguchi "<shigio@tama-
com.com>", modified by Barrie Slaymaker "<barries@slaysys.com>".
splitpath(), splitdir(), catpath() and catdir() by Barrie Slaymaker.
COPYRIGHT
Copyright (c) 2004 by the Perl 5 Porters. All rights reserved.
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.8.6 2007-05-21 File::Spec(3)
