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
    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 Knig, 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.

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 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 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 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 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 OSs.

    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 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 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 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

AUTHORS
    Kenneth Albanowski <kjahds@kjahds.com>, Andy Dougherty
    <doughera@lafayette.edu>, Andreas Knig
    <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.

