Quickly and visually compare arbitrary hex in streams
synaesthesia (with the British spelling) takes an input stream and adds colouring to any strings of hex it detects. It is designed to allow you to compare hashes and the like at a glance.
Examples:
md5 download.zip | synaesthesia
openssl rsa -noout -modulus < cert.key | synaesthesia
It uses a deterministic algorithm to assign colours so you can run it on the same hash on different computers and it should still work.
On OSX at least, --emoji or -e replaces the colourised text with a selection of emoji chosen to be fairly distinct from each other (ie, only one smiley face; only one snowman).