Basic blank bash script

This is my starting blank bash scipt.

To check your script for proper syntax and prevent bugs use ShellCheck.

#!/bin/bash
#####
#ident "@(#) blank_script v 1.0 2017/02/16"
#
#  Author: Raymond Keckler
#
#
#
########################################

## color settings
RED='\033[0;31m'
GREEN='\033[0;32m'
NC='\033[0m' # No Color

## Give usage message if the command was wrong
function usage()
{
    echo -e "${RED}usage: blank_script --field1 <info> --field2 <info> --field3 <info>${NC}"
    echo -e "${GREEN}Basic info on a blank_script${NC}"
}  

function main()
{
    firstvar=$1
    secondvar=$2
    thirdvar=$3
}


##
# Main
#
DEBUG="false"

while [ "$1" != "" ]; do
    case $1 in
        --field1 )	shift
                 	var1=$1
                 	;;
	--field2 ) 	shift
			var2=$1
			;;
	--field3 )	shift
			var3=$1
			;;
        * )         	usage
                    	exit 1
    esac
    shift
done

if [[ ("$var1" == "") || ("$var2" == "") || ("$var3" == "") ]] ; then
    usage
    exit 1
fi

main "$var1" "$var2" "$var3"