File::Spec(3p) Perl Programmers Reference Guide File::Spec(3p)NAMEFile::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 per-
formed on file specifications (usually called "file names",
but not to be confused with the contents of a file, or
Perl's file handles), such as concatenating several direc-
tory 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 sys-
tems, each set of OS specific routines is available in a
separate module, including:
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 available 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.
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File::Spec(3p) Perl Programmers Reference Guide File::Spec(3p)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 probably 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 ending with a directory. But remove the trailing
slash from the resulting string, because it doesn't look
good, isn't necessary and confuses 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 complete 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.
$rootdir = File::Spec->rootdir();
tmpdir
Returns a string representation of the first writable
directory from a list of possible temporary directories.
Returns the current directory if no writable temporary
directories are found. The list of directories checked
depends on the platform; e.g. File::Spec::Unix checks
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$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 equivalents.)
@paths = File::Spec->no_upwards( @paths );
case_tolerant
Returns a true or false value indicating, respectively,
that alphabetic case is not or is significant when compar-
ing file specifications.
$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( $path );
This does not consult the local filesystem on Unix, Win32,
OS/2, or Mac OS (Classic). It does consult the working
environment for VMS (see "file_name_is_absolute" in
File::Spec::VMS).
path
Takes no argument. Returns the environment variable
"PATH" (or the local platform's equivalent) as a list.
@PATH = File::Spec->path();
join
join is the same as catfile.
splitpath
Splits a path in to volume, directory, and filename por-
tions. On systems with no concept of volume, returns ''
for volume.
($volume,$directories,$file) = File::Spec->splitpath( $path );
($volume,$directories,$file) = File::Spec->splitpath( $path, $no_file );
For systems with no syntax differentiating filenames from
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directories, 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 equivalent 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 systems that have the concept of a volume or that
have path syntax that differentiates files from direc-
tories.
Unlike just splitting the directories on the separator,
empty directory 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 concatenated. A '/' is inserted if need be.
On other OSes, $volume is significant.
$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() is used. If
$base is relative, then it is converted to absolute form
using "rel2abs()". This means that it is taken to be rela-
tive to 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
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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 rela-
tive to cwd().
No checks against the filesystem are made. On VMS, there
is interaction 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() is used. If
$base is relative, then it is converted to absolute form
using "rel2abs()". This means that it is taken to be rela-
tive to 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
"canonpath()".
No checks against the filesystem are made. On VMS, there
is interaction 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.
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File::Spec(3p) Perl Programmers Reference Guide File::Spec(3p)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@newman.upenn.edu>". OS/2 support by Ilya Zakhare-
vich "<ilya@math.ohio-state.edu>". Mac support by Paul
Schinder "<schinder@pobox.com>", and Thomas Wegner
"<wegner_thomas@yahoo.com>". abs2rel() and rel2abs() written
by Shigio Yamaguchi "<shigio@tamacom.com>", modified by Bar-
rie Slaymaker "<barries@slaysys.com>". splitpath(), split-
dir(), 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.
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