找不到字符串后如何在shell中停止? [英] how to stop while do in shell once a string is not found?

问题描述

我有这个脚本:

#!/bin/bash
while [ true ]
do

    if tail -1 /tmp/test | grep 'line3'
    then
        echo found
        sleep 5
    else
        echo not found
    fi
done

每5秒钟查找一次 line3 .找不到 line3 后，如何使脚本停止?

It looks for line3 every 5 seconds. How do I make the script stop once line3 is not found ?

推荐答案

目前尚不清楚您为什么在 tail |中加入 while [true] 的原因.grep 和 if，然后，else 作为 while 循环可以使用您的子句作为测试本身:

It is a little unclear why you are including while [ true ] around your tail | grep and if, then, else as the while loop can use your clause as the test itself:

#!/bin/bash

while tail -1 /tmp/test | grep 'line3'
do
    echo found
    sleep 5
done

echo "not found"

如果 包裹 if，then，else ，这没什么不对.

There is nothing wrong with wrapping if, then, else in while [ true ], it is just less than optimal.

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