Production-Ready Bash Script Template

Beginner10 minTrending

Create a reusable bash script template with strict error handling, argument parsing, logging, cleanup traps, and help text.

Prerequisites

-Bash 4.0+ installed
-Basic shell scripting knowledge

Steps

Create the script file with a shebang

Start with the bash shebang and strict mode flags to catch errors early.

$ cat > script.sh << 'SCRIPTEOF' #!/usr/bin/env bash set -euo pipefail IFS=$'\n\t' SCRIPTEOF

Use #!/usr/bin/env bash instead of #!/bin/bash for portability across systems where bash may not be in /bin.

Add script metadata and constants

Define the script name, version, and directory for reliable relative paths.

$ echo 'readonly SCRIPT_NAME="$(basename "$0")"' >> script.sh && echo 'readonly SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"' >> script.sh && echo 'readonly VERSION="1.0.0"' >> script.sh

Add a usage function

Create a help function that documents all options and arguments.

$ cat >> script.sh << 'USAGEEOF' usage() { cat << EOF Usage: ${SCRIPT_NAME} [OPTIONS] <argument> Options: -h, --help Show this help message -v, --verbose Enable verbose output -d, --dry-run Show what would be done without executing --version Show version Examples: ${SCRIPT_NAME} -v /path/to/target ${SCRIPT_NAME} --dry-run /path/to/target EOF exit 0 } USAGEEOF

Add a cleanup trap

$ cat >> script.sh << 'TRAPEOF' cleanup() { local exit_code=$? # Remove temp files, restore state, etc. rm -f "${TMPFILE:-}" 2>/dev/null || true exit "$exit_code" } trap cleanup EXIT ERR INT TERM TRAPEOF

Always quote variable expansions in cleanup to avoid word splitting on filenames with spaces.

Add a logging function

Create colored log functions for consistent output formatting.

$ cat >> script.sh << 'LOGEOF' log() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [INFO] $*"; } warn() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [WARN] $*" >&2; } error() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [ERROR] $*" >&2; } die() { error "$*"; exit 1; } LOGEOF

Make the script executable and test it

Set execute permissions and verify the script runs without errors.

$ chmod +x script.sh && ./script.sh --help

Full Script

full-script.sh

#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'

readonly SCRIPT_NAME="$(basename "$0")"
readonly SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
readonly VERSION="1.0.0"

# --- Logging ---
log()   { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [INFO]  $*"; }
warn()  { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [WARN]  $*" >&2; }
error() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [ERROR] $*" >&2; }
die()   { error "$*"; exit 1; }

# --- Cleanup ---
cleanup() {
  local exit_code=$?
  rm -f "${TMPFILE:-}" 2>/dev/null || true
  exit "$exit_code"
}
trap cleanup EXIT ERR INT TERM

# --- Usage ---
usage() {
  cat << EOF
Usage: ${SCRIPT_NAME} [OPTIONS] <argument>

Options:
  -h, --help      Show this help message
  -v, --verbose   Enable verbose output
  -d, --dry-run   Show what would be done
  --version       Show version

Examples:
  ${SCRIPT_NAME} -v /path/to/target
EOF
  exit 0
}

# --- Main ---
VERBOSE=false
DRY_RUN=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    -h|--help)    usage ;;
    -v|--verbose) VERBOSE=true; shift ;;
    -d|--dry-run) DRY_RUN=true; shift ;;
    --version)    echo "$VERSION"; exit 0 ;;
    -*)           die "Unknown option: $1" ;;
    *)            break ;;
  esac
done

[[ $# -lt 1 ]] && die "Missing required argument. Use --help for usage."

TARGET="$1"
log "Processing: $TARGET"

FAQ

Discussion

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#!/usr/bin/env bash set -euo pipefail IFS=$'\n\t' readonly SCRIPT_NAME="$(basename "$0")" readonly SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)" readonly VERSION="1.0.0" # --- Logging --- log() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [INFO] $*"; } warn() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [WARN] $*" >&2; } error() { echo "[$(date +'%Y-%m-%d %H:%M:%S')] [ERROR] $*" >&2; } die() { error "$*"; exit 1; } # --- Cleanup --- cleanup() { local exit_code=$? rm -f "${TMPFILE:-}" 2>/dev/null || true exit "$exit_code" } trap cleanup EXIT ERR INT TERM # --- Usage --- usage() { cat << EOF Usage: ${SCRIPT_NAME} [OPTIONS] <argument> Options: -h, --help Show this help message -v, --verbose Enable verbose output -d, --dry-run Show what would be done --version Show version Examples: ${SCRIPT_NAME} -v /path/to/target EOF exit 0 } # --- Main --- VERBOSE=false DRY_RUN=false while [[ $# -gt 0 ]]; do case "$1" in -h|--help) usage ;; -v|--verbose) VERBOSE=true; shift ;; -d|--dry-run) DRY_RUN=true; shift ;; --version) echo "$VERSION"; exit 0 ;; -*) die "Unknown option: $1" ;; *) break ;; esac done [[ $# -lt 1 ]] && die "Missing required argument. Use --help for usage." TARGET="$1" log "Processing: $TARGET"