Shell Scripting Basics

A shell script is just a file of commands you'd type anyway — the fastest way to automate backups, deploys, and chores on Linux.

#A safe skeleton

#!/usr/bin/env bash
set -euo pipefail        # exit on error, undefined var, or failed pipe

name="${1:-world}"       # first arg, default "world"
echo "Hello, $name"

for f in *.log; do
    [ -e "$f" ] || continue
    gzip "$f"
done

#The building blocks

#The rules that save you

Always set -euo pipefail and always quote your variables ("$var"). Unquoted variables and silent failures cause the scariest bugs — a script that deletes the wrong thing because a variable was empty.

For anything complex, reach for Python — but for gluing commands together, Bash is unbeatable. Run scripts on a schedule with Cron and Scheduling.

Related: Cron and Scheduling · Understanding systemd · File Permissions Explained