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File::Spec(3p)   Perl Programmers Reference Guide  File::Spec(3p)


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 operating sys-
       tems.

       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 ) ;

       catdir
         Concatenate two or more directory names to form a com-
         plete 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 OS2. 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 direc-
         tory.

             $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();




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File::Spec(3p)   Perl Programmers Reference Guide  File::Spec(3p)


       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 is not or is significant when comparing
         file specifications.

             $is_case_tolerant = File::Spec->case_tolerant();

       file_name_is_absolute
         Takes as 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 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.



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File::Spec(3p)   Perl Programmers Reference Guide  File::Spec(3p)


       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 OSs.

       catpath()
         Takes volume, directory and file portions and returns an
         entire path. Under Unix, $volume is ignored, and direc-
         tory and file are concatenated.  A '/' is inserted if
         need be.  On other OSs, $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 desti-
         nation 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.




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File::Spec(3p)   Perl Programmers Reference Guide  File::Spec(3p)


         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

AUTHORS
       Kenneth Albanowski <kjahdsATkjahds.com>, Andy Dougherty
       <dougheraATlafayette.edu>, Andreas Koenig
       <A.KoenigATfranz.DE>, Tim Bunce
       <Tim.BunceATig.uk.  VMS support by Charles Bailey <bai-
       leyATnewman.edu>.  OS/2 support by Ilya Zakharevich
       <ilyaATmath.edu>.  Mac support by Paul Schinder
       <schinderATpobox.com>, and Thomas Wegner <weg-
       ner_thomasATyahoo.com>.  abs2rel() and rel2abs() written by
       Shigio Yamaguchi <shigioATtamacom.com>, modified by Barrie
       Slaymaker <barriesATslaysys.com>.  splitpath(), splitdir(),
       catpath() and catdir() by Barrie Slaymaker.



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