For the above..question..same added $perl -e 'use Time::Piece; print Time::Piece->strptime("2006-02-31", "%Y-%m-%d");' will give you some date but $perl -e 'use Time::Piece; print Time::Piece->strptime("2006-02-32", "%Y-%m-%d");' will throw error. That is, anything less than 32 accepts as valid day.