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Manual Reference Pages  -  FILE::DIRCOMPARE (3)

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File::DirCompare - Perl module to compare two directories using callbacks.



  use File::DirCompare;

  # Simple diff -r --brief replacement
  use File::Basename;
  File::DirCompare->compare($dir1, $dir2, sub {
    my ($a, $b) = @_;
    if (! $b) {
      printf "Only in %s: %s\n", dirname($a), basename($a);
    } elsif (! $a) {
      printf "Only in %s: %s\n", dirname($b), basename($b);
    } else {
      print "Files $a and $b differ\n";

  # Version-control like Deleted/Added/Modified listing
  my (@listing, @modified);     # use closure to collect results
  File::DirCompare->compare(old_tree, new_tree, sub {
    my ($a, $b) = @_;
    if (! $b) {
      push @listing, "D   $a";
    } elsif (! $a) {
      push @listing, "A   $b";
    } else {
      if (-f $a && -f $b) {
        push @listing, "M   $b";
        push @modified, $b;
      } else {
        # One file, one directory - treat as delete + add
        push @listing, "D   $a";
        push @listing, "A   $b";


File::DirCompare is a perl module to compare two directories using a callback, invoked for all files that are ’different’ between the two directories, and for any files that exist only in one or other directory (’unique’ files).

File::DirCompare has a single public compare() method, with the following signature:

  File::DirCompare->compare($dir1, $dir2, $sub, $opts);

The first three arguments are required - $dir1 and $dir2 are paths to the two directories to be compared, and $sub is the subroutine reference called for all unique or different files. $opts is an optional hashref of options - see OPTIONS below.

The provided subroutine is called for all unique files, and for every pair of ’different’ files encountered, with the following signature:

  $sub->($file1, $file2)

where $file1 and $file2 are the paths to the two files. For ’unique’ files i.e. where a file exists in only one directory, the subroutine is called with the other argument ’undef’ i.e. for:

  $sub->($file1, undef)
  $sub->(undef, $file2)

the first indicates $file1 exists only in the first directory given ($dir1), and the second indicates $file2 exists only in the second directory given ($dir2).


The following optional arguments are supported, passed in using a hash reference after the three required arguments to compare() e.g.

  File::DirCompare->compare($dir1, $dir2, $sub, {
    cmp             => $cmp_sub,
    ignore_cmp      => 1,
    ignore_unique   => 1,
    matches         => $matches_sub,

cmp By default, two files are regarded as different if their contents do not match (tested with File::Compare::compare). That default behaviour can be overridden by providing a ’cmp’ subroutine to do the file comparison, returning zero if the two files are equal, and non-zero if not.

E.g. to compare using modification times instead of file contents:

  File::DirCompare->compare($dir1, $dir2, $sub, {
    cmp => sub { -M $_[0] <=> -M $_[1] },

ignore_cmp If you want to see all corresponding files, not just ’different’ ones, set the ’ignore_cmp’ flag to tell File::DirCompare to skip its file comparison checks i.e.

  File::DirCompare->compare($dir1, $dir2, $sub,
    { ignore_cmp => 1 });

ignore_unique If you want to ignore files that only exist in one of the two directories, set the ’ignore_unique’ flag i.e.

  File::DirCompare->compare($dir1, $dir2, $sub,
    { ignore_unique => 1 });

matches Subroutine to be called for file pairs that match, with the following signature:

  $sub->($file1, $file2)

These pairs are ordinarily ignored (unless ignore_cmp is set).


File::Dircmp, which provides similar functionality (and whose directory walking code I’ve adapted for this module), but a simpler reporting-only interface, something like the first example in the SYNOPSIS above.


Gavin Carr <>

Thanks to Robin Barker for a bug report and fix for glob problems with whitespace.


Copyright 2006-2012 by Gavin Carr <>.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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perl v5.20.3 DIRCOMPARE (3) 2012-10-10

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