AdvancedAutomation

Lab: automate it

Practice automation decisions — scheduling, Makefiles, CI shell scripts, and debugging.

Lab · optionalBashAdvanced10 min

Recommended first

Debugging Scripts

By the end of this lesson you will be able to:

Choose the right scheduling mechanism for a task
Structure a Makefile target correctly
Write a CI shell script that fails fast and loudly
Diagnose automation failures from symptoms

Optional scenario lab. Automation lives or dies on the small decisions: when to use cron vs. a queue, how to make a Makefile target idempotent, how to surface failures in CI. Practice them here.

Scenarios: automation

1.
You need to run a cleanup script every night at 2 AM on a single server. Best tool?
cronA MakefileA GitHub Actions workflow triggered by pushA systemd service with Restart=always
2.
Your Makefile has a clean target that deletes build artifacts. You also have a file named clean in the project root. What happens when you run make clean?
make runs the clean target as normalmake sees the file is up to date and skips the targetmake errors with 'no rule to make target'make deletes the file named clean
3.
A CI shell script should use set -e so that the script exits immediately if any command fails.
TrueFalse
4.
A cron job ran last night but produced no output and the expected file wasn't created. First thing to check?
Reboot the serverRedirect the script's stdout and stderr to a log file to capture any error outputDelete the cron entry and recreate itSwitch to a different scripting language
5.
A deployment script that can safely be run twice without leaving the system in a broken state is called:
AtomicIdempotentConcurrentDeterministic

The automation mindset: make failures loud, make reruns safe, and always capture output — silent cron jobs are the hardest kind to debug.

Finished reading? Mark it complete to track your progress.

Debugging Scripts

Use set -x trace mode, bash -n syntax checks, PS4 customisation, shellcheck, and quoting/word-splitting analysis to find and fix Bash bugs.