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File::Spec(3)          Perl Programmers Reference Guide          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 confused with the contents of a file, or Perl's file handles), such as concatenating sev-
       eral 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, 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 oper-
       ating 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 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 directo-
         ries.  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 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
         comparing 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 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 destina-
         tion 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 relative 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 relative, it is converted to absolute form using "rel2abs()".  This means that it is taken to be
         relative 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 relative 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.

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 "<KWILLIAMSATcpan.org>".

       The vast majority of the code was written by Kenneth Albanowski "<kjahdsATkjahds.com>", Andy Dougherty
       "<dougheraATlafayette.edu>", Andreas Koenig "<A.KoenigATfranz.DE>", Tim Bunce
       "<Tim.BunceATig.uk>".  VMS support by Charles Bailey "<baileyATnewman.edu>".  OS/2 support by Ilya
       Zakharevich "<ilyaATmath.edu>".  Mac support by Paul Schinder "<schinderATpobox.com>", and Thomas Weg-
       ner "<wegner_thomasATyahoo.com>".  abs2rel() and rel2abs() written by Shigio Yamaguchi "<shigioATtamacom.com>",
       modified by Barrie Slaymaker "<barriesATslaysys.com>".  splitpath(), splitdir(), catpath() and catdir() by Bar-
       rie 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 v5.8.8                       2001-09-21                     File::Spec(3)