# break

结束for，while或until循环。

## 概要

```
break [n]
```

## 主要用途

* 结束for，while或until循环，可指定退出几层循环。

## 参数

n（可选）：大于等于1的整数，用于指定退出几层循环。

## 返回值

返回成功除非n小于1。

## 例子

```
# break的可选参数n缺省值为1。
# 从外层for循环继续执行。
for((i=3;i>0;i--)); do
  for((j=3;j>0;j--)); do
    if((j==2)); then
      # 换成break 1时结果一样
      break
    fi
  printf "%s %s\n" ${i} ${j}
  done
done
# 输出结果
3 3
2 3
1 3
```

```
# 当n为2时：
# 退出两层循环，结束。
for((i=3;i>0;i--)); do
  for((j=3;j>0;j--)); do
    if((j==2)); then
      break 2
    fi
  printf "%s %s\n" ${i} ${j}
  done
done
# 输出结果
3 3
```

### 注意

1. 该命令是bash内建命令，相关的帮助信息请查看`help`命令。


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://hezhiqiang.gitbook.io/linux/ming-ling/break.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.