Oops ... I forgot to account for daylight savings in the call to mktime. Sorry about that. #!/usr/bin/env perl use integer; use strict; use POSIX qw(mktime strftime tzset); # set $tzdir and $bogon as you see fit my $tzdir = '/usr/share/zoneinfo'; my $bogon = '^(right|posix|Etc|SystemV)/|\.tab$' .'|^(Factory|UTC|localtime|posixrules)$' .'|^GMT.|^(..T|.ST\d.DT)$'; my %mill = (); chdir $tzdir or die "$tzdir: $!\n"; foreach my $zone (`find * -type f -print`) { chomp $zone; next if $zone =~ m:$bogon:o; $ENV{'TZ'} = $zone; tzset; my $when = mktime(0, 0, 0, 1, 0, 2000-1900, 0, 0, -1); $mill{$when} = [] unless exists $mill{$when}; push @{$mill{$when}}, $zone; } foreach my $when (sort { $a <=> $b } keys %mill) { my %zones = (); foreach my $zone (@{$mill{$when}}) { my ($dev, $ino) = stat $zone; next unless defined $ino; $zones{"$dev.$ino"} = [] unless exists $zones{"$dev.$ino"}; push @{$zones{"$dev.$ino"}}, $zone; } print strftime "%b %d %H:%M UTC\n", gmtime $when; foreach my $devino (keys %zones) { print ' 'x4, join('|', sort @{$zones{$devino}}), "\n"; } } exit 0;