How to generate a UUID on a Mac

With uuidgen

macOS includes uuidgen:

uuidgen

It prints a random version 4 UUID in uppercase, like 3F2504E0-4F89-41D3-9A0C-0305E82C3301.

Lowercase, straight to the clipboard

uuidgen | tr '[:upper:]' '[:lower:]' | pbcopy

Many databases and APIs use lowercase, so this is the version most developers want.

Several at once

for i in {1..5}; do uuidgen; done

From the notch

NotchMind, which I make, has UUID v4 on its Developer Tools page. Open the notch, pick it, press the button, then Copy result. No Terminal needed. See developer tools in the notch.

Is it unique?

A version 4 UUID has 122 random bits. You can treat a newly generated one as unique for any practical purpose.