为什么getopts仅在第一次使用? [英] Why does getopts only work the first time?

问题描述

为什么此选项仅在首次使用时起作用，而后每隔一次被忽略?就像不使用该选项时将其重置.

Why does this option only work the first time it's used, then ignored every other time? It's like it's being reset when the option is not used.

这是我的职能:

testopts() {
    local var="o false"
    while getopts "o" option; do
        case "${option}" in
            o)
                var="o true"
                ;;
        esac
    done
    echo $var
}

运行它时，仅在首次传递该选项时才返回true.

When running it, it only returns true when passing the option for the first time.

$ testopts
o false
$ testopts -o
o true
$ testopts -o
o false

推荐答案

您需要在函数顶部添加以下行:

You need to add this line at top of your function:

OPTIND=1

否则，由于每次都在同一个shell中运行该函数，因此在shell中连续调用该函数不会将其重置为空.

Otherwise successive invocation of the function in shell are not resetting this back since function is being run in the same shell every time.

根据help getopts:

每次调用它时，getopts都会将下一个选项放在 shell变量$name，如果不存在，则初始化名称，以及 下一个要处理到shell中的参数的索引 变量OPTIND.每次shell或 OPTIND都初始化为1. 一个shell脚本被调用.

Each time it is invoked, getopts will place the next option in the shell variable $name, initializing name if it does not exist, and the index of the next argument to be processed into the shell variable OPTIND. OPTIND is initialized to 1 each time the shell or a shell script is invoked.

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