# The while-loop

## Synopsis

    while <LIST1> ; do
      <LIST2>
    done

## Description

The while-loop is relatively simple in what it does: it executes the
[command list](../../syntax/basicgrammar.md#lists) `<LIST1>` and if the exit
code of it was 0 (TRUE) it executes `<LIST2>`. This happens again and
again until `<LIST1>` returns FALSE.

This is exactly the opposite of the [until
loop](../../syntax/ccmd/until_loop.md).

:!: Like all loops (both `for`-loops, `while` and `until`), this loop
can be

-   terminated (broken) by the `break` command, optionally as `break N`
    to break `N` levels of nested loops
-   forced to immediately do the next iteration using the `continue`
    command, optionally as `continue N` analog to `break N`

### Return status

The return status is the one of the last command executed in `<LIST2>`,
or `0` (`TRUE`) if none was executed.

## Examples

## Portability considerations

## See also

-   Internal: [The until loop](../../syntax/ccmd/until_loop.md)
-   Internal: [code examples of the read builtin
    command](../../commands/builtin/read.md#code_examples) to see how you can
    loop over lines