# 删除字符串的最后字符

在shell编程中，经常需要移除字符串最后一些字符，在bash中，有一个非常方便的方法：

```bash
#!/bin/bash

v="some string.rtf"
v2=${v::-4}
echo "$v --> $v2"
```

不过，这个方法对bash版本有一定要求，需要 bash 4+

更为通用的方法结合使用 `rev` 和 `cut` ，原理是先通过 `rev` 反转字符串，然后通过 `cut` 将反转后的字符串开头n个字符移除，然后再次反转字符串

```bash
echo "hello world" | rev | cut -c5- | rev
```

返回结果就是

```
hello w
```

## 参考

* [Delete the last character of a string using string manipulation in shell script](https://unix.stackexchange.com/questions/144298/delete-the-last-character-of-a-string-using-string-manipulation-in-shell-script)
* [How to remove last n characters from a string in Bash?](https://stackoverflow.com/questions/27658675/how-to-remove-last-n-characters-from-a-string-in-bash)


---

# 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://huataihuang.gitbook.io/cloud-atlas-draft/develop/shell/bash/delete_last_char_of_string.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.