bash-master

Bash Scripting Mastery

Scope and platform contract

This skill targets Bash itself, wherever Bash runs - Linux, macOS, WSL, Git Bash / MSYS2 on Windows, and Bash-based container images. It does not cover native PowerShell: a PowerShell script is a different language and should use powershell-master. On Windows, bash-master assumes the user is running Bash inside Git Bash, WSL, or a similar Bash environment, and addresses the MSYS path-translation quirks that result.

Repository conventions

Project-level conventions (Windows backslashes in tool calls, documentation discipline, etc.) live in the agent body and the windows-path-master plugin. This skill focuses on Bash content; do not duplicate that boilerplate here.

Quick reference

#!/usr/bin/env bash
set -euo pipefail  # Exit on error, undefined vars, pipe failures
IFS=$'\n\t'        # Safe word splitting
# Run shellcheck your_script.sh before deployment.
# Test on every target platform before production.

Bash-portability quick check:

# Linux/macOS:       Full bash features
# Git Bash (Windows): Most features, some system calls missing (no systemd, /proc differs)
# WSL:               Effectively Linux; /mnt/c for Windows filesystem
# Containers:        Depends on base image - alpine ships /bin/sh, not bash
# POSIX mode:        Use /bin/sh and avoid bashisms

When to use this skill

Always activate for:

• Writing or modifying any bash/shell script
• Reviewing or refactoring existing scripts
• Debugging shell script failures
• DevOps automation, CI/CD pipelines, system administration
• Cross-environment Bash portability (Linux <-> macOS <-> WSL <-> Git Bash <-> container)

Do not use this skill for:

• PowerShell scripts - use powershell-master
• Batch (.cmd/.bat) scripting
• Generic command help unrelated to scripting

Core principles

1. Safety first

Every script should open with the safety preamble:

#!/usr/bin/env bash
set -e            # Exit on any error
set -u            # Exit on undefined variable
set -o pipefail   # Catch failures mid-pipeline
set -E            # Inherit ERR trap into functions
IFS=$'\n\t'       # Avoid word splitting on spaces

readonly SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
readonly SCRIPT_NAME="$(basename "${BASH_SOURCE[0]}")"