There's no reason for estimator.sh to exist. Just make it a subcommand under yarn or whatever.
In it's current form, it's missing a BUNCH of boilerplate that makes certain functionality completely fail.
start/stop-estimator.sh is full of copypasta that doesn't actually do anything/work correctly. Additionally, if estimator.sh doesn't exist, neither does this since yarn --daemon start/stop will do everything as necessary.