Lily
Posted on Aug 29
Originally published at dev.to
This is a follow-up to my earlier post, "Automating a config migration with a one-shot launchd job." This time the trigger is an external event with a known end-of-life date (Fable 5 shutting down on 2026-07-07), and the question is how to design a launchd job you can set up today, have it fire only on that day, and have it remove itself once it's done.
Some deprecations come with a date stamped on them, and hand-editing a config on that exact day is the kind of chore you forget. But I also didn't want a script waking up every morning to rewrite the same JSON for no reason. What I landed on was a three-part set: a date gate, a backed-up jq rewrite, and a self-unload.
