Software
Engineer
← All courses
Intermediate·10 lessons·106 min

Shell Scripting

Write shell scripts that survive contact with a real machine. Variables, quoting, exit status, loops, functions, and redirection — in portable POSIX sh, the shell that exists in every container and CI image.

Start — Your First Script
  1. 01Your First ScriptA file, a shebang, and the two ways to run it. 10 min
  2. 02VariablesHolding a value, and the two rules about spaces and quotes. 9 min
  3. 03Quoting and WildcardsWhat the shell does to your line before anything runs. 9 min
  4. 04Exit Status and testHow a script finds out whether the last thing worked. 12 min
  5. 05LoopsEvery file, every line, until it works — and the empty-glob trap. 10 min
  6. 06Case and ArgumentsBranching on a value, and reading what the script was called with. 10 min
  7. 07Command SubstitutionCapturing a program’s output as a value, and where the newlines go. 10 min
  8. 08FunctionsNaming a block, and why return doesn’t return a value. 11 min
  9. 09Redirection and Here-DocumentsThree streams, and why 2>&1 has to come second. 12 min
  10. 10Scripts That Surviveset -eu, trap, mktemp — the habits that make a script safe to run unattended. 13 min