Cheat Sheet - Bash

In diesem Artikel sammle ich alle möglichen hilfreichen Tipps & Snippets für das Schreiben von einem Bash Skript.

Yes / No selector

while true; do
    _log ""
    read -rp "Ready to update credential - proceed? (yes/no) " yn
    case $yn in
    yes|y) break;;
        no|n) _log "ERROR" "Aborted!";;
        * ) _log "Invalid response!";;
    esac
done

Logging

_log() {
  if [ "$TERM" == "xterm-256color" ]; then
    textRed=$(tput setaf 1)
    textYellow=$(tput setaf 3)
    textBlue=$(tput setaf 4)
    textNormal=$(tput sgr0)
  fi

  if [ "${1}" == "WARN" ]; then
    printf '%-7s %s\n' "${textYellow}[$1]${textNormal}" "$2" >&2
    return 0
  elif [ "${1}" == "ERROR" ]; then
    printf '%-7s %s\n' "${textRed}[$1]${textNormal}" "$2" >&2
    exit 1
  elif [ "${1}" == "INFO" ]; then
    printf '%-7s %s\n' "${textBlue}[$1]${textNormal}" "$2"
    return 0
  else
    echo "$1"
  fi
}

_log "INFO" "This is an info message"
_log "ERROR" "This is an error message"
_log "WARN" "This is a warn message"

Args Command selector

case "$1" in
  init)
    init
    _log "INFO" "PolyCV initialized!"
    ;;
  init-start)
    init
    _log "INFO" "PolyCV initialized!"
    start
    _log "INFO" "PolyCV started!"
    ;;
  start)
    start
    _log "INFO" "PolyCV started!"
    ;;
  stop)
    stop
    _log "INFO" "PolyCV stopped!"
    ;;
  purge)
    purge
    ;;
  *)
  echo "Usage: $0 {init|init-start|start|stop|purge\"server command\"}"
  exit 1
  ;;
esac

Add Debug env var

# Check if DEBUG environment variable is set
if [ -n "$DEBUG" ]; then
    # If DEBUG is set, enable verbose output and exit on error/unset variable
    set -eux
else
    # Otherwise, just exit on error
    set -e
fi

Photo by J B: https://www.pexels.com/photo/herd-of-wildebeests-on-the-field-17980174/

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