commit 0ad0e43211843b87e7203f7a72f50a501c95ae9a
Author: Peter J. Holzer <hjp@hjp.at>
Date:   Sun Jan 12 21:06:46 2014 +0100

    Find duplicates of files in one dir in another

diff --git a/finddup b/finddup
new file mode 100755
index 0000000..73a2b7a
--- /dev/null
+++ b/finddup
@@ -0,0 +1,78 @@
+#!/usr/bin/perl
+
+=head1 NAME
+
+finddup - yet another tool for finding duplicates
+
+=cut
+
+use v5.10;
+no autovivification 'fetch';
+use File::Find;
+use File::stat;
+use File::Slurp;
+use Digest::SHA qw(sha256_hex);
+
+my ($needledir, $haystackdir) = @ARGV;
+
+my $haystack;
+
+find(sub {
+        if (-f $_) {
+            my $st = lstat($_);
+            my $size = $st->size;
+            my $hash = "";
+            unless ($haystack->{$size}{$hash}) {
+                $haystack->{$size}{$hash} = [];
+            }
+            push $haystack->{$size}{$hash}, { path => $File::Find::name, 
+                                              size => $size,
+                                              dev  => $st->dev,
+                                              ino  => $st->ino,
+                                            };
+        }
+    }, 
+    $haystackdir
+);
+
+find(
+    {
+        wanted => sub {
+                    if (-f $_) {
+                        my $st = lstat($_);
+                        my $size = $st->size;
+                        my $found;
+                        if ($haystack->{$size}) {
+                            if ($haystack->{$size}{""}) {
+                                for my $file (@{ $haystack->{$size}{""} }) {
+                                    my $content = read_file($file->{path});
+                                    my $hash = sha256_hex($content);
+                                    unless ($haystack->{$size}{$hash}) {
+                                        $haystack->{$size}{$hash} = [];
+                                    }
+                                    push $haystack->{$size}{$hash}, $file;
+                                }
+                                delete $haystack->{$size}{""};
+                            }
+                            my $content = read_file($_);
+                            my $hash = sha256_hex($content);
+                            if ($haystack->{$size}{$hash}) {
+                                for my $file (@{ $haystack->{$size}{$hash} }) {
+                                    unless ($st->dev == $file->{dev} && $st->ino == $file->{ino}) {
+                                        say "$_ -> $file->{path}";
+                                        $found = 1;
+                                    }
+                                }
+                            }
+                        }
+                        unless ($found) {
+                            say "$_ (NONE)";
+                        }
+                    }
+                },
+        no_chdir => 1,
+    },
+    $needledir
+);
+
+# vim: tw=132 sw=4 expandtab