Loading... 预备知识: [ -z "$1" ] -z 空 $1 命令行后的第一个参数 [ -z "$1" ] && usage; ./build-nanopc-t4.sh -M 此时不会执行usage函数 ./build-nanopc-t4.sh 此时会执行usage函数 if [ $? != 0 ] ; then exit 1; fi $? 上个命令的退出状态,或函数的返回值 Last modification:August 18, 2021 © Allow specification reprint Support Appreciate the author AliPayWeChat Like 0 如果觉得我的文章对你有用,请随意赞赏