getopts使用

#!/bin/bash#如果存在没有设置的变量退出脚本#set -o nounsetset -u#set -o errexitset -eecho $becho $aecho $*while getopts ":a:bc:" opt    do        case $opt in            a) echo "a has the argument:$OPTARG"               echo $OPTIND;;            b) echo "$OPTIND";;            c) echo "$OPTIND"               echo "c has the argument:$OPTARG";;            ?) echo "invalid option"               exit 1;;        esac    doneecho $OPTINDshift $(($OPTIND-1))