lib/perl5/5.6.1/FindBin.pm

   1 # FindBin.pm
   2 #
   3 # Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
   4 # This program is free software; you can redistribute it and/or modify it
   5 # under the same terms as Perl itself.
   6
   7 =head1 NAME
   8
   9 FindBin - Locate directory of original perl script
  10
  11 =head1 SYNOPSIS
  12
  13  use FindBin;
  14  use lib "$FindBin::Bin/../lib";
  15
  16  or
  17
  18  use FindBin qw($Bin);
  19  use lib "$Bin/../lib";
  20
  21 =head1 DESCRIPTION
  22
  23 Locates the full path to the script bin directory to allow the use
  24 of paths relative to the bin directory.
  25
  26 This allows a user to setup a directory tree for some software with
  27 directories E<lt>rootE<gt>/bin and E<lt>rootE<gt>/lib and then the above example will allow
  28 the use of modules in the lib directory without knowing where the software
  29 tree is installed.
  30
  31 If perl is invoked using the B<-e> option or the perl script is read from
  32 C<STDIN> then FindBin sets both C<$Bin> and C<$RealBin> to the current
  33 directory.
  34
  35 =head1 EXPORTABLE VARIABLES
  36
  37  $Bin         - path to bin directory from where script was invoked
  38  $Script      - basename of script from which perl was invoked
  39  $RealBin     - $Bin with all links resolved
  40  $RealScript  - $Script with all links resolved
  41
  42 =head1 KNOWN BUGS
  43
  44 if perl is invoked as
  45
  46    perl filename
  47
  48 and I<filename> does not have executable rights and a program called I<filename>
  49 exists in the users C<$ENV{PATH}> which satisfies both B<-x> and B<-T> then FindBin
  50 assumes that it was invoked via the C<$ENV{PATH}>.
  51
  52 Workaround is to invoke perl as
  53
  54  perl ./filename
  55
  56 =head1 AUTHORS
  57
  58 FindBin is supported as part of the core perl distribution. Please send bug
  59 reports to E<lt>F<perlbug@perl.org>E<gt> using the perlbug program included with perl.
  60
  61 Graham Barr E<lt>F<gbarr@pobox.com>E<gt>
  62 Nick Ing-Simmons E<lt>F<nik@tiuk.ti.com>E<gt>
  63
  64 =head1 COPYRIGHT
  65
  66 Copyright (c) 1995 Graham Barr & Nick Ing-Simmons. All rights reserved.
  67 This program is free software; you can redistribute it and/or modify it
  68 under the same terms as Perl itself.
  69
  70 =cut
  71
  72 package FindBin;
  73 use Carp;
  74 require 5.000;
  75 require Exporter;
  76 use Cwd qw(getcwd abs_path);
  77 use Config;
  78 use File::Basename;
  79 use File::Spec;
  80
  81 @EXPORT_OK = qw($Bin $Script $RealBin $RealScript $Dir $RealDir);
  82 %EXPORT_TAGS = (ALL => [qw($Bin $Script $RealBin $RealScript $Dir $RealDir)]);
  83 @ISA = qw(Exporter);
  84
  85 $VERSION = "1.42";
  86
  87 BEGIN
  88 {
  89  *Dir = \$Bin;
  90  *RealDir = \$RealBin;
  91
  92  if($0 eq '-e' || $0 eq '-')
  93   {
  94    # perl invoked with -e or script is on C<STDIN>
  95
  96    $Script = $RealScript = $0;
  97    $Bin    = $RealBin    = getcwd();
  98   }
  99  else
 100   {
 101    my $script = $0;
 102
 103    if ($^O eq 'VMS')
 104     {
 105      ($Bin,$Script) = VMS::Filespec::rmsexpand($0) =~ /(.*\])(.*)/s;
 106      ($RealBin,$RealScript) = ($Bin,$Script);
 107     }
 108    else
 109     {
 110      my $IsWin32 = $^O eq 'MSWin32';
 111      unless(($script =~ m#/# || ($IsWin32 && $script =~ m#\\#))
 112             && -f $script)
 113       {
 114        my $dir;
 115        foreach $dir (File::Spec->path)
 116         {
 117         my $scr = File::Spec->catfile($dir, $script);
 118         if(-r $scr && (!$IsWin32 || -x _))
 119          {
 120           $script = $scr;
 121
 122           if (-f $0)
 123            {
 124             # $script has been found via PATH but perl could have
 125             # been invoked as 'perl file'. Do a dumb check to see
 126             # if $script is a perl program, if not then $script = $0
 127             #
 128             # well we actually only check that it is an ASCII file
 129             # we know its executable so it is probably a script
 130             # of some sort.
 131
 132             $script = $0 unless(-T $script);
 133            }
 134           last;
 135          }
 136        }
 137      }
 138
 139      croak("Cannot find current script '$0'") unless(-f $script);
 140
 141      # Ensure $script contains the complete path incase we C<chdir>
 142
 143      $script = File::Spec->catfile(getcwd(), $script)
 144        unless File::Spec->file_name_is_absolute($script);
 145
 146      ($Script,$Bin) = fileparse($script);
 147
 148      # Resolve $script if it is a link
 149      while(1)
 150       {
 151        my $linktext = readlink($script);
 152
 153        ($RealScript,$RealBin) = fileparse($script);
 154        last unless defined $linktext;
 155
 156        $script = (File::Spec->file_name_is_absolute($linktext))
 157                   ? $linktext
 158                   : File::Spec->catfile($RealBin, $linktext);
 159       }
 160
 161      # Get absolute paths to directories
 162      $Bin     = abs_path($Bin)     if($Bin);
 163      $RealBin = abs_path($RealBin) if($RealBin);
 164     }
 165   }
 166 }
 167
 168 1; # Keep require happy
 169