# Introduction

```
hostnamectl set-hostname xxx
hostnamectl ste-hostname ${HOSTNAME,,} # 主机名大写to小写

lsof /path/file    # 查看哪个进程在使用这个文件
lsof -p <pid>    # 查看进程打开的文件
lsof -i:3306    # 查看端口号为3306的进程所打开的文件

sed -i "s#search#replace#g" file # 替换file文件中的字符串

dig -t A xxx.default.svc.cluster.local. @10.96.0.10    # DNS查询
nslookup xxx.default.svc.cluster.local. 10.96.0.10    # DNS查询

"ctrl" + "]"    # telnet退出方式
```


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# 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://pshizhsysu.gitbook.io/linux/master.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.