[notes] Finding where an environment variable came from in fish

Because I often wonder this, and because fish makes it easy, and because writing it down here might help you and will definitely help me remember it! Assumed audience: Other software developers who use fish shell. Last night, I was trying to figure out where a particular environment variable had come from, and went searching1 for a way to figure that out. I was delighted, as I often am, to find that fish makes it incredibly easy. If you want to know where and how SOME_ENVIRONMENT_VARIABLE was set, you just type: $ set --show SOME_ENVIRONMENT_VARIABLE Fish will helpfully print out something like this (assuming SOME_ENVIRONMENT_VARIABLE was set to the string cool-beans, and was set with set -Ux SOME_ENVIRONMENT_VARIABLE cool-beans): $SOME_ENVIRONMENT_VARIABLE: set in universal scope, exported, with 1 elements $SOME_ENVIRONMENT_VARIABLE[1]: |cool-beans| This is one of those things that feels obvious once you first see it in action, and yet… As far as I know — and I’d be happy to be…