produce-a-lowercase-v4-uuid.md

Produce A Lowercase V4 UUID

There are a variety of ways to produce a v4 UUID on Unix-based machines. Of the options I listed in that post, my favorite is the uuidgen command. My only gripe with it is that it produces an all uppercase UUID.

$ uuidgen
B7918C26-12AE-4093-B6DA-0D7D41C59FB6

Often when I need a UUID, it is to plug in as the ID value for some test data in a system that is using lowercase UUIDs. For the sake of consistency, I'd like it to be lowercase as well.

The tr command comes in handy for this because I can _tr_anslate the uppercase characters to lowercase ones.

$ uuidgen | tr '[:upper:]' '[:lower:]'
ed817cf3-8f70-4838-82bc-8e5b328c0b93

So now anytime I need a lowercase UUID, I hit ctrl-r and search back for either uuid or lower and find this command pretty quickly.