See whether you can produce a pattern to match a standard time format. All the following should be acceptable: 12:00am, 5:00pm, 8:30AM. These should probably not be accepted: 3:00,2:60am, 99:00am, 3:0pm. #### #!/usr/bin/perl -w use strict; use warnings; print "Type in the current time!\n"; my $input = ; while($input) { if($input =~ m/(\d)*(\d):(\d)(\d)(\w)(\w)/ | $input =~ m/(\d)*(\d):(\d)(\d)(\s)(\w)(\w)/) { if($1 > 1 || $2 > 2 || $3 > 6) { print "That is not a valid time!\n"; print "Type the time again.\n"; $input = ; } else { print "That is a valid time!\n"; $input = 0; } } else { print "Please be more specific.\n"; $input = ; } } #### Last login: Thu Aug 18 11:28:44 on ttys000 youngs-mac-mini:~ fenimore$ cd ~/Documents youngs-mac-mini:Documents fenimore$ perl TimeChecker.pl Type in the current time! 4:90 Please be more specific. 4:30AM Use of uninitialized value $1 in numeric gt (>) at TimeChecker.pl line 13, line 2. That is not a valid time! Type the time again. 12:30PM That is a valid time! youngs-mac-mini:Documents fenimore$ #### if($1 > 1 || $2 > 2 || $3 > 6)