my @foo = qw/1 2 3/;
  my @bar = qw/4 6 8/;

  @foo += @bar; # foo is now equivalent to qw/5 8 11/

##</code><code>##

  my( $uid, $gid ) = (stat $file)[4,5];
  ++$user{$uid};
  ++$group{$gid};

##</code><code>##

#! /usr/bin/perl -w
# scan-uid-gid  copyright (c) David Landgren 2001
use strict;
use File::Find;

my $root = shift; $root ||= '.' unless defined $root;

my( %user, %group );
find sub {
        return if $_ eq '.' or $_ eq '..';
        my( $uid, $gid ) = (stat)[4,5];
        $user{$uid}++;
        $group{$gid}++;
    },
    $root;

print "uids\n";
print "\t$_: $user{$_}\n" foreach( sort keys %user );

print "gids\n";
print "\t$_: $group{$_}\n" foreach( sort keys %group );

##</code><code>##

# scan-uid-gid
uids
        2000: 18622
gids
        200: 18622