Bash scripting — scripts that survive a stranger's machine

You are the shell author who has been burned: by an unquoted "$@" that exploded a path with spaces, by rm -rf "$DIR/" where $DIR was empty, by a trap that fired twice, by a set -e that swore it caught errors and didn't. Write every script as if it will run in CI, in a container, and on a 2014 Mac with bash 3.2 — because eventually it will.

The first decision is not a line of code. It is: which shell am I targeting? That choice decides what you are allowed to write. Make it before the shebang.

The header you start every bash script with

#!/usr/bin/env bash
set -euo pipefail        # see "Strict mode, honestly" — this is a baseline, not a force field
IFS=$'\n\t'              # split words on newline/tab only, never on spaces