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File::Spec(3) |
User Contributed Perl Documentation |
File::Spec(3) |
File::Spec - portably perform operations on file names
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');
This module is designed to support operations commonly performed 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 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 König, 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,
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.
- 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
$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 files in a directory (such as from
"readdir()"), strip out
'.' and '..'.
SECURITY NOTE: This does NOT filter paths containing
'..', like
'../../../../etc/passwd', only literal matches
to '.' and '..'.
@paths = File::Spec->no_upwards( readdir $dirhandle );
- case_tolerant
- Returns a true or false value indicating, respectively, that alphabetic
case is not or is significant when comparing file specifications. Cygwin
and Win32 accept an optional drive argument.
$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( $path );
This does not consult the local filesystem on Unix, Win32,
OS/2, or Mac OS (Classic). It does consult the working environment for
VMS (see "file_name_is_absolute" in File::Spec::VMS).
- path
- Takes no argument. Returns the environment variable
"PATH" (or the local platform's
equivalent) as a list.
@PATH = File::Spec->path();
- join
- join is the same as catfile.
- splitpath
- Splits a path in to volume, directory, and filename portions. On systems
with no concept of volume, returns '' for volume.
($volume,$directories,$file) =
File::Spec->splitpath( $path );
($volume,$directories,$file) =
File::Spec->splitpath( $path, $no_file );
For systems with no syntax differentiating filenames from
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
directories.
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::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
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::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 "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.
File::Spec::Unix, File::Spec::Mac, File::Spec::OS2, File::Spec::Win32,
File::Spec::VMS, File::Spec::Functions, ExtUtils::MakeMaker
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
König
"<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 Zakharevich
"<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
Barrie Slaymaker
"<barries@slaysys.com>".
splitpath(), splitdir(), catpath() and catdir()
by Barrie Slaymaker.
Copyright (c) 2004-2013 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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