Scripts

Saving a job so it runs again.

A first script

A file starting with #!/bin/bash, made executable with chmod +x, runs as a command. Variables, if statements and for loops turn a sequence of commands into a tool.

set -euo pipefail at the top makes a script stop on the first error rather than continuing.
Quote your variables. Unquoted paths with spaces cause most script bugs.

Scheduling

cron runs a command on a schedule and systemd timers do the same with better logging. Both are how backups and cleanups happen without anyone remembering.