linuxexpert-practice-labs/labs/linux-plus/4-5-1-ai-responsible-use/README.md

Linux+ 4.5.1: Using AI responsibly

The review habit, without any AI tool: checking a generated script with ShellCheck, and rewriting it so it fails safely.

Before you start

Work as root, so ~ is /root. The VM needs internet access to install ShellCheck (from EPEL on RHEL relatives). The lab only checks that ~/ai-cleanup.sh and ~/cleanup.sh don't exist yet. Write answers to the files in /root/lab-answers/. Don't run the chapter's clean-up line: the lab grades ~/cleanup.sh, and le-lab reset removes the files.

Tasks

1. Save the chapter's "AI-written" ~/ai-cleanup.sh, and find its problems before running anything. Install ShellCheck, run it on the script, and save its report in /root/lab-answers/1.
2. Write the safer ~/cleanup.sh: with set -euo pipefail, it takes a directory and a number of days as required arguments (with a usage message), refuses a number of days that isn't a number, and deletes only *.tar.gz files directly in that directory that are older than that many days, printing each one. Test it on throwaway files in /tmp/bk, and make sure ShellCheck has nothing to say about it.

Hints

• dnf install ShellCheck (EPEL) or apt install shellcheck; shellcheck ~/ai-cleanup.sh > /root/lab-answers/1.
• ${1:?usage: cleanup.sh DIR DAYS}, [[ $days =~ ^[0-9]+$ ]], find "$dir" -maxdepth 1 -type f -name '*.tar.gz' -mtime +"$days" -print -delete; touch -d '20 days ago'.
• The chapter's step 3 (writing a prompt) isn't graded.