如何在 Bash 中跳出循环?

问题描述

我想编写一个 Bash 脚本来处理文本，这可能需要一个 while 循环.

I want to write a Bash script to process text, which might require a while loop.

例如，C 中的 while 循环:

For example, a while loop in C:

int done = 0;
while(1) {
  ...
  if(done) break;
}

我想编写一个与此等效的 Bash 脚本.但是我通常使用的以及我读过的所有经典示例都展示了这个:

I want to write a Bash script equivalent to that. But what I usually used and as all the classic examples I read have showed, is this:

while read something;
do
...
done

它没有提供关于如何做 while(1){} 和 break; 的帮助，这在 C 中定义明确并广泛使用，我没有为标准输入读取数据.

It offers no help about how to do while(1){} and break;, which is well defined and widely used in C, and I do not have to read data for stdin.

谁能帮我写一个与上述 C 代码等效的 Bash 代码?

Could anyone help me with a Bash equivalent of the above C code?

推荐答案

在 bash 中并没有什么不同.

It's not that different in bash.

workdone=0
while : ; do
  ...
  if [ "$workdone" -ne 0 ]; then
      break
  fi
done

: 是无操作命令；它的退出状态始终为 0，因此循环运行直到 workdone 被赋予一个非零值.

: is the no-op command; its exit status is always 0, so the loop runs until workdone is given a non-zero value.

有很多方法可以设置和测试workdone的值以退出循环；我上面展示的那个应该可以在任何兼容 POSIX 的 shell 中工作.

There are many ways you could set and test the value of workdone in order to exit the loop; the one I show above should work in any POSIX-compatible shell.

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