#!/usr/bin/env perl
  use File::Spec;
  
  if ( @ARGV < 2 ) {
    print STDERR "usage: ln.pl input1 input2 dest-dir
  " .
      "This script does a soft link of input1, input2, etc." .
      "to dest-dir, using relative links where possible
  " .
      "Note: input-n and dest-dir may both be absolute pathnames,
  " .
      "or relative pathnames, relative to the current directlory.
  ";
    exit(1);
  }  
  
  $dir = pop @ARGV;
  if ( ! -d $dir ) {
    print STDERR "ln.pl: last argument must be a directory ($dir is not a directory)
  ";
    exit(1);
  }
  
  $ans = 1; # true.
  
  $absdir = File::Spec->rel2abs($dir); # Get $dir as abs path.
  defined $absdir || die "No such directory $dir";
  foreach $file (@ARGV) {
    $absfile =  File::Spec->rel2abs($file); # Get $file as abs path.
    defined $absfile || die "No such file or directory: $file";
    @absdir_split = split("/", $absdir);
    @absfile_split = split("/", $absfile);
  
    $newfile = $absdir . "/" . $absfile_split[$#absfile_split]; # we'll use this
    # as the destination in the link command.
    $num_removed = 0;
    while (@absdir_split > 0 && $absdir_split[0] eq $absfile_split[0]) {
      shift @absdir_split;
      shift @absfile_split;
      $num_removed++;
    }
    if (-l $newfile) { # newfile is already a link -> safe to delete it.
      unlink($newfile); # "unlink" just means delete.
    }
    if ($num_removed == 0) { # will use absolute pathnames.
      $oldfile = "/" . join("/", @absfile_split);
      $ret = symlink($oldfile, $newfile);
    } else {
      $num_dots = @absdir_split;
      $oldfile = join("/", @absfile_split);
      for ($n = 0; $n < $num_dots; $n++) {
        $oldfile = "../" . $oldfile;
      }
      $ret = symlink($oldfile, $newfile);
    }
    $ans = $ans && $ret;
    if (! $ret) {
      print STDERR "Error linking $oldfile to $newfile
  ";
    }
  }
  
  exit ($ans == 1 ? 0 : 1);