Using shift in bash

gistfile1.txt

while [ "$1" != "" ]; do
    if [ "$1" == "--hostname" ]; then
	HOSTNAME=${2}; shift
	echo "Hostname Defined: ${HOSTNAME}"
    elif [ "$1" == "--base-image" ]; then
	BASEIMAGE=${2}; shift
	echo "Base-image defined: ${BASEIMAGE}"
    elif [ "$1" == "--test" ]; then
	TEST=true; shift
    elif [ "$1" == "--help" ]; then
         usage
exit 0
    else
echo "Unknown Option ${1}!"
usage
exit 1;
    fi
    shift
done