There are a few reasons you shouldn’t use this in proper programs. If you’re the sort of person that thinks hacky Bash scripts are acceptable then sure, use it there.

1. It isn’t cross-platform. Not available on Mac/Windows.
2. There are several types of UUID with different properties. This doesn’t let you choose which one to use.
3. To make programs deterministic (really useful for testing!) you want to be able to seed all their randomness with a specific seed so that it generates the same UUID each time you run it. (Obviously in normal use you would use a random seed.)

Yeah but please don’t actually use this. Use a proper UUID library that works cross-platform and lets you choose the UUID type and can be seeded etc.