bash 中的动态 case 语句 [英] Dynamic case statement in bash

问题描述

我正在研究如何在 bash 脚本中创建动态 case 语句.

I'm trying to figure out how to create a dynamic case statement in a bash script.

例如，假设我有一个带有以下内容的 awk 语句的输出

For example, let's say I have the output of an awk statement with the following contents

red
green
blue

在这种情况下，输出可以随时更改.

In this scenario, the output can change at any time.

如果此 awk 输出中包含一个值，我将尝试执行不同的逻辑.

I'm trying to then execute different logic if a value is included in this awk output.

因此，如果上面的数据在 $list 中，那么从概念上讲，我想执行以下操作:

So if the data above is in $list, then I'd conceptually like to do something like:

case "${my_var}" in
    $list)
        .....
    something_else)
        .....
esac

我正在尝试使用它来构建动态自定义选项卡完成功能(请参阅 http://www.debian-administration.org/article/An_introduction_to_bash_completion_part_2 了解一些背景.

I'm trying to use this to build a dynamic custom tab completion function (see http://www.debian-administration.org/article/An_introduction_to_bash_completion_part_2 for some background).

有什么想法吗?

谢谢.

推荐答案

case 语句可能不是完成这项工作的正确工具.如果您将 awk 输出存储在一个数组中，那么您可以遍历该数组以查找其中是否有选项，并且作为奖励还可以找出是哪个索引.

A case statement is probably not the right tool for the job. If you store the awk output in an array then you can loop through the array to find if a choice is in it, and as a bonus can figure out which index that is, too.

#!/bin/bash

# Store command output in an array so each word is a separate array item.    
list=($(echo $'red
green
blue'))
my_var=blue

for ((i = 0; i < ${#list}; i++)); do
    if [[ ${list[$i]} = $my_var ]]; then
        echo "found at index $i"
        break
    fi
done

if ((i == ${#list})); then
    echo "not found"
fi

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