While循环在Bash脚本？ [英] While loop in Bash script?

问题描述

我不习惯写的bash脚本，而谷歌并没有搞清楚帮助什么是错的这个脚本：

 ＃！/斌/庆典
而读MYLINE
做
DONE回声你好
而读线
做
DONE退出0
 

我得到的输出是：

  ./ basic.agi：4号线：语法附近意外的标记错误完成
./basic.agi：4号线：'做'
 

和我的庆典的版本是：

  GNU bash中，3.2.25版（1） - 释放（i686的-红帽Linux的GNU的）
 

感谢您。

---

编辑：。该脚本确定，当while循环不为空

而我在它...我希望当用户输入什么，即退出循环。只需按下回车键，但猛砸不断循环。我怎样才能退出循环？

 同时读取MYLINE
做
        回声$ {} MYLINE
DONE回声你好
而读线
做
        真正
DONE退出0
 

解决方案

您不能有一个空循环。如果你想要一个占位符，只要使用真正。

 ＃！/斌/庆典
而读MYLINE
做
    真正
DONE
 

，或者更可能的是，做一些与输入有用的：

 ＃！/斌/庆典
而读MYLINE
做
    回声您输入[$行]
DONE
 

---

至于你的第二个问题，关于如何退出循环时，用户只需presses <大骨节病> ENTER 有没有别的，你可以做一些事情：

 ＃！/斌/庆典
在线阅读
而[[$行=]！]做
    回声您输入[$行]
    在线阅读
DONE
 

I'm not used to writing Bash scripts, and Google didn't help in figuring out what is wrong with this script:

#!/bin/bash
while read myline
do
done

echo "Hello"
while read line
do
done

exit 0

The output I get is:

./basic.agi: line 4: syntax error near unexpected token 'done'
./basic.agi: line 4: 'done'

and my bash version is:

GNU bash, version 3.2.25(1)-release (i686-redhat-linux-gnu)

Thank you.

---

Edit: The script works OK when the while loop isn't empty.

While I'm at it... I expected to exit the loop when the user typed nothing, ie. simply hit the Enter key, but Bash keeps looping. How can I exit the loop?

while read myline
do
        echo ${myline}
done

echo "Hello"
while read line
do
        true
done

exit 0

解决方案

You can't have an empty loop. If you want a placeholder, just use true.

#!/bin/bash
while read myline
do
    true
done

or, more likely, do something useful with the input:

#!/bin/bash
while read myline
do
    echo "You entered [$line]"
done

---

As for your second question, on how to exit the loop when the user just presses ENTER with nothing else, you can do something:

#!/bin/bash
read line
while [[ "$line" != "" ]] ; do
    echo "You entered [$line]"
    read line
done

这篇关于While循环在Bash脚本？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！