Bash scripting for real work: safe scripts that automate

Most Bash scripts start as a few commands pasted into a file. They work until the day a file name contains a space, a command fails halfway, or the script runs from cron with a different environment. This course teaches you to write scripts that survive those days.

What you will learn

• Quoting rules that prevent the most common and most dangerous bugs
• Strict mode, exit codes and error handling, including where strict mode surprises people
• Variables, arrays, parameter expansion and functions
• Parsing options and arguments with getopts and clear usage messages
• Temporary files, traps and cleanup
• Logging, locking and running safely from cron and systemd timers
• Linting with ShellCheck, formatting with shfmt and testing with Bats

How the course works

Every concept is shown with a small script you run and then break on purpose. We collect the good habits into a template you can start every new script from. In the last section we write three complete tools you can adapt: a backup script with retention, a log cleanup job and a deployment helper.

We target Bash 5 on Linux. macOS ships an old Bash 3.2 by default and uses zsh as the login shell, so I show how to install a current Bash with Homebrew if you practise on a Mac.

When not to use Bash

We also discuss honestly when a script has outgrown Bash and should be rewritten in Python or Go.