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File::Spec(3) - File::Spec - portably perform operations on file names - man 3 File::Spec

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



NAME
       File::Spec - portably perform operations on file(1,n) 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(1,n) specifications (usually called "file(1,n) names", but not to be con-
       fused with the contents of a file(1,n), or Perl's file(1,n) handles), such as
       concatenating several directory and file(1,n) 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(7,n,1 builtins) of OS specific routines is available in(1,8) 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(7,n) 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 ) ;

       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(3,n), because it doesn't look(1,8,3 Search::Dict) good, isn't necessary and con-
         fuses OS2. Of course, if(3,n) 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(3,n) representation of the current directory.

             $curdir = File::Spec->curdir();

       devnull
         Returns a string(3,n) representation of the null device.

             $devnull = File::Spec->devnull();

       rootdir
         Returns a string(3,n) representation of the root directory.

             $rootdir = File::Spec->rootdir();

       tmpdir
         Returns a string(3,n) representation of the first writable directory from
         a list of possible temporary directories.  Returns the current direc-
         tory if(3,n) 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(3,n) representation of the parent directory.

             $updir = File::Spec->updir();

       no_upwards
         Given a list of file(1,n) 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 is not or is significant when comparing file(1,n) specifications.

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

       file_name_is_absolute
         Takes as argument a path and returns true if(3,n) 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(1,8) 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(1,n)
         join(1,n) is the same as catfile.

       splitpath
         Splits a path in(1,8) to volume, directory, and filename portions. On sys-
         tems with no concept of volume, returns '' for volume.

             ($volume,$directories,$file(1,n)) = File::Spec->splitpath( $path );
             ($volume,$directories,$file(1,n)) = File::Spec->splitpath( $path, $no_file );

         For systems with no syntax differentiating filenames from directo-
         ries, assumes that the last file(1,n) 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 OSs.

       catpath()
         Takes volume, directory and file(1,n) portions and returns an entire path.
         Under Unix, $volume is ignored, and directory and file(1,n) are concate-
         nated.  A '/' is inserted if(3,n) need be.  On other OSs, $volume is sig-
         nificant.

             $full_path = File::Spec->catpath( $volume, $directory, $file(1,n) );

       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 rela-
         tive, 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(3,n) $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(1,8) 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 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() is used. If $base is rela-
         tive, 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(3,n) $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(1,8) 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

AUTHORS
       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 Zakharevich <ilya@math.ohio-state.edu>.  Mac support by Paul
       Schinder <schinder@pobox.com>, and Thomas Wegner <weg-
       ner_thomas@yahoo.com>.  abs2rel() and rel2abs() written by Shigio Yam-
       aguchi <shigio@tamacom.com>, modified by Barrie Slaymaker <bar-
       ries@slaysys.com>.  splitpath(), splitdir(), catpath() and catdir() by
       Barrie Slaymaker.



perl v5.8.5                       2001-09-21                     File::Spec(3)

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