color bash prompt with timestamp ahead

color_msg.sh

#!/bin/bash
color_msg() {
    if [ $# -gt 2 ]; then
        echo -e "\033[1;31mUsage: ${0} [error|-e|info|-i|warn|-w] "your message".\033[0m"
    fi
    now_time=$(date '+[%Y/%m/%d %H:%M:%S]')
    case ${1} in
        # red
        error|-e )
            echo -e "${now_time}\t\033[1;31m${2}\033[0m"
        ;;
        # green
        info|-i )
            echo -e "${now_time}\t\033[1;32m${2}\033[0m"
        ;;
        # yellow
        warn|-w )
            echo -e "${now_time}\t\033[1;33m${2}\033[0m"
        ;;
        # normal
        * )
            echo -e "${now_time}\t${1}"
    esac
}