note Anonymous Monk I prefer a iso 8601 <C>$ perl -MDateTime -le"print DateTime->now->strftime( q!%F-%H-%M-%S%z! );" 2011-04-06-07-04-11+0000 $ perl -MDateTime -le"print DateTime->now( qw[ time_zone local ] )->strftime( q!%F-%H-%M-%S%z! );" 2011-04-06-00-04-29-0700 </C> or double digit suffix <C> foo.pl-00 foo.pl-01 </c> With a iso 8601 timestamp at the top of the file 897538 897538 9