Compare non-standard time format to now() in linux

I run debian on a raspberry pi and want to see if a given timestamp is older than X hours. This would be trivial if the timestamp was in a standard format, but unfortunately that is not the case. The timestamp has the following format: November 5, 2016 at 12:50AM or November 14, 2016 at 04:35PM I'm looking for a tool that can take in a timestamp in a given input-format, and convert to another time format. I can use any tools as long as they are available on debian/raspberry pi. What I'm looking for is something like this: #!/bin/bash timeout="1440" # 24 hours = 1440 minutes now=$(date +"%Y%m%d%H%M") # = 201611271814 timestamp_raw="November 5, 2016 at 12:50AM" timestamp=$(convert "$timestamp_raw" --inputformat +"%B %e, %Y at %I:%M%p" --outputformat +"%Y%m%d%H%M") # this command is fictitious but should produce something like 201611050050 comparedate=$(expr $now - $timeout) # = now() - 24 hours if [ $timestamp -ge $comparedate ]; then echo 'yes'; fi Can you point me in the right direction?