exsample for show batch log message.

show_log.sh

#!/bin/bash

usage() {

cat << EOT

  usage $0 [OPTIONS]

  OPTIONS
    -h show this usage
    -q not show log message (without error message)
EOT
}

# if it is not empty, does not show log
QUIET=

## log function ##
log() {
  test -z "$QUIET" && echo "$*"
}

debug() {
  log "DEBUG $*"
}

info() {
  log "INFO $*"
}

warn() {
  log "WARN $*"
}

err() {
  # output to STDERR
  echo "ERR $*" 1>&2
}

while getopts "hq" option; do
  case $option in
    q)
      QUIET=1
      ;;
    \?)
      echo "wrong option."
      usage
      exit 1
      ;;
    h)
      usage
      exit 0
      ;;
  esac
done
shift $(($OPTIND - 1))