shell-scripts

name	shell-scripts
description	Use when creating or editing shell scripts, Bash files, deployment scripts, build scripts, or writing shell commands into files; emphasizes strict mode, portability, safety, and maintainability.

Shell Script Best Practices

Apply these conventions to every shell script you write or modify.

Required Header

Every script must start with:

#!/bin/bash
set -euo pipefail
cd "$(dirname "$0")"

What strict mode does

Flag	Effect
set -e	Exit immediately on any non-zero exit code
set -u	Treat unset variables as errors (catches typos like $BUKCET)
set -o pipefail	Fail pipelines if any command fails, not just the last one

Why cd "$(dirname "$0")" matters

Scripts should work regardless of where they're invoked from. This line changes to the script's own directory so relative paths (like ./build.sh or cp -r media out/) resolve correctly.

Only omit if the script genuinely needs to operate in the caller's working directory — and add a comment explaining why.

Additional Conventions

• Quote all variable expansions: "$var", "${arr[@]}" — unquoted variables break on spaces and glob characters.
• Use [[ ]] over [ ]: Double brackets prevent word splitting and support pattern matching.
• Prefer $() over backticks: Clearer, nestable, and avoids escaping issues.
• No unnecessary dependencies: Prefer shell builtins over external commands when equivalent (e.g., [[ -f file ]] over test -f file).