223

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

For example, a while loop in C:

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

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

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.

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

codeforester
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lulyon
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2 Answers2

296

It's not that different in bash.

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

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

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.

vvvvv
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chepner
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82
while true ; do
    ...
    if [ something ]; then
        break
    fi
done
lurker
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