bash-script-writing

name	bash-script-writing
description	Write clean, modular bash scripts with proper error handling. Triggers on 'write a script', 'bash script', 'shell script', or 'automate with bash'.

Modular Bash Script Writing

Follow this structure when writing bash scripts.

Script Template

Place main() immediately after variables so the workflow is visible at file top.

#!/usr/bin/env bash
set -euo pipefail

################################################################################
# Script Title
################################################################################
#
# OVERVIEW
# --------
# Brief description of what this script does
#
# USAGE
# -----
#   script-name arg1 arg2
#
# CONFIGURATION
# -------------
# Environment variables or config requirements
#
################################################################################

# Colors
green='\033[0;32m'
blue='\033[0;34m'
yellow='\033[1;33m'
red='\033[0;31m'
nc='\033[0m'

# Configuration
VAR_ONE=${VAR_ONE:-default}
VAR_TWO=${VAR_TWO:?VAR_TWO is required}

################################################################################
# Main Orchestration
################################################################################

main() {
  parse_arguments "$@"
  step_one
  step_two
  log "Complete!"
}

################################################################################
# Helper Functions
################################################################################

log() { echo -e "${green}==>${nc} ${1}"; }
info() { echo -e "${blue}Info:${nc} ${1}"; }
warn() { echo -e "${yellow}Warning:${nc} ${1}"; }
error() { echo -e "${red}Error:${nc} ${1}" >&2; exit 1; }

################################################################################
# Core Functions
################################################################################

function_name() {
  log "What this function does..."
  # Implementation
  log "Complete"
}

################################################################################
# Script Execution
################################################################################

main "$@"

Function Guidelines

• Name clearly: Verb-based names (setup_directory, validate_config)
• One purpose: If you need "and" to describe it, split it
• Log progress: Start with log "...", end with status
• Keep focused: 5-20 lines per function
• Group with section headers: Use #### dividers between logical groups

Code Quality

• Lint with shellcheck: Run shellcheck script.sh before considering a script done. Address all warnings, or explicitly disable with a # shellcheck disable=SCxxxx comment explaining why.
• Use meaningful exit codes: 0 for success, 1 for general errors, 2 for misuse. Reserve higher codes for specific failure modes callers need to distinguish.