Bash library to echo messages with a colour depending on the provided log level

bash_log_utils.sh

#!/usr/bin/env sh

BLUE='\033[0;34m'
NC='\033[0m' # No Color

log() {
  # Log levels: error (red), info (green), warn (yellow), critical (bold red)
  case $1 in
    error) level='\033[0;31mERROR' ;;
    info) level='\033[0;32mINFO' ;;
    warn) level='\033[0;33mWARN' ;;
    critical) level='\033[1;31mCRITICAL' ;;
    *) return 111
  esac

  # Shift arguments so that $* is only the message
  shift

  # Colourised timestamp
  ts="[$BLUE$(date '+%F %T %Z')$NC]"
  # Log message
  printf "%b %b: %s$NC\n" "$ts" "$level" "$*"
}