To be on the safe side it's probably best to allow whitespaces (or none) in some more places which would turn the regex into: $time =~ /^\s*(\d{1,2})\s*:\s*(\d\d)\s*([APM]{2})\s*$/The \s* matches zero or more whitespaces and as many as possible (greedy). So this allows for any of the following (_ equals whitespace):

_12:00_AM__
1_:_00_PM
2:20AM
[download]

And then you could allow for leaving out of AM/PM and assuming a 24 hour clock .... but /me gets carried away ;)

-- Hofmator