5.1. Shell Scripting

Shell scripting is the foundational automation skill — before Ansible, before Terraform, Linux administrators automated with bash. Scripts still dominate one-off tasks, system initialization, and anywhere Python is unavailable. The exam tests practical scripting: conditionals, loops, functions, input handling, and debugging.

💡 First Principle: A shell script is just a sequence of commands that the shell executes in order, with the ability to store values (variables), make decisions (if/case), repeat actions (for/while), and encapsulate reusable logic (functions). Everything you type interactively can go in a script.

⚠️ Common Misconception: Many candidates assume that shell scripts are simple but brittle. Properly written scripts with error handling (set -euo pipefail), input validation, and meaningful exit codes are robust and production-grade. The fragility comes from skipping these practices, not from bash itself.