#!/usr/bin/perl $num = 0; open F, ">datafile" or die "Can't open $f : $!"; for ($i = 1;$i<=1000;$i++){ if ($num < 10) { $lead = "00"; } elsif ($num < 100 && $num >= 10) { $lead = "0"; } else { $lead = ''; } print F qq() . "\n"; $num++; } close F;