Linux help commands and so on

Q: Why write a blog?

A: To tell the truth, just contact to write a blog or particularly confused, do not know what to say, and do not know how much to say. But then I feel Marco and some good friends are right, blog is to comb the knowledge, people will forget, forget to look can deepen.

Okay, here we are. In today's command, the command of Bash, the most commonly used query command under the Linux system, should belong to "--help (note two '-')

1, because help in our philosophy is the most helpful meaning, because the meaning of English helps the term is helpful.

Here I give an example: for example, there is a command to create a directory mkdir, assuming we do not know what it means, we can use the # mkdir--help to get help information.

650) this.width=650, "style=" width:644px;height:178px; "title=" 1.jpg "src=" Http://s3.51cto.com/wyfs02/M01/38/9C /wkiom1o0cghagy97aajxsjov22u756.jpg "width=" 415 "height=" "alt=" Wkiom1o0cghagy97aajxsjov22u756.jpg "/>"

Chinese signals: Create catalogs (if they are not in advance) if they do not exist beforehand.

The following is also a list of the long and short options information, note the-M,-P,-V,-Z option. I personally think "--help" is the most intuitive to get help for the auxiliary command options. Here directory capitalization indicates that the directory name you want to replace, such as/jerry, is Mkdir/jerry.

2, said the second time first to say a concept, Linux commands roughly divided into two categories, one is the internal shell from the command, can be called internal command. The second type is the external command, the external command itself, is a standalone executable file, the command name is the program file name.

We can use the Type command, the format is type Command,command for the command name, such as 650) this.width=650; "title=" 2CD command. jpg "src=" http://s3.51cto.com/wyfs02 /m01/38/a0/wkiol1o0drjywhc6aabtjmtxw4e361.jpg "alt=" wkiol1o0drjywhc6aabtjmtxw4e361.jpg "/>,CD command shows is a shell Builtin that this is a shell built-in command that satisfies the requirements, you can use the second method to get the help directly with the built-in command of the Assist command +shell

650) this.width=650; "title=" 3.jpg "src=" Http://s3.51cto.com/wyfs02/M00/38/A2/wKioL1O0EJORfIXHAAEbV9f0qyM849.jpg " alt= "Wkiol1o0ejorfixhaaebv9f0qym849.jpg"/>

Show Change the shell working directory changes working directory. Help is more concise than the first command, English can not understand the direct Youdao dictionary, but the object of the help command must be the shell built-in commands, if you look at external commands. 650) this.width=650; "title=" 4.jpg "src=" Http://s3.51cto.com/wyfs02/M00/38/A6/wKiom1O0Er6hUPU8AACOR8vOuW4325.jpg " alt= "Wkiom1o0er6hupu8aacor8vouw4325.jpg"/> It will say no Help topics match

Because the man command is not a shell built-in command, there is no help situation.

Third, please out of our man God to solve the help, the last is always the main!

Man= men, can think so, but the result is not, man is the abbreviation of English Manual, manual in the noun part of speech has the meaning of the manual. Because of the complexity of man, we will look at it in several parts.

Since it is a manual, there will be sections of chapters, yes. Man has an important 8, and now it could be 9 parts.

Manual chapters:

Standard manual Chapters

1 Users Command user commands

2 system calls refers to a program running under User space that requests to the kernel to enter a service that is running higher privileges

3 C Libraries C library Functions

4 Devices and special documents DEVICES and special files

5 format and conventions of files file Formats and conventions

6 games! Games et

7 Miscellaneous Miscellanea

8 Systems Management and daemons system Administration tools and Deamons

The daemon, which is usually called the daemon process, is the background service process in Linux. It is a long-lived process, usually independent of the control terminal and periodically performs some sort of task or waits to handle certain occurrences.

Read the man chapters and see which chapters the commands are under in the Man manual and use the Whatis command to get information. Whatis based on the database, this library is updated periodically for the system, and the manual update is makewhatis.

And we found that the # Man CD appears behind the CD (1), and for this we can use the Man (#) #表示数字 COMMAND to help with the specific chapters

Finish the chapter concept, and then look at the use of the man Operation command

Usually a man command, the screen will show a large amount of English documents, and there are a lot of unfinished parts, we usually use the space bar for the next page of the chapter

What to do with the previous page, use the B key.

What if I want to see the next line? Then use the ENTER key to perform the next line of flip screen operation

What if I want to return to the line? You can use the K key to do the previous row

And I found that when you connect to Linux with a remote terminal, you can also press CTRL + J/K for the next line and the previous line.

The ctrl+f operation is to turn the half-screen down, while the ctrl+u can be turned up half-screen

Ctrl+h can count the information of the command's Help file, which appears in black on the last line of the screen.

If you want to index a keyword lookup, you can do so with a/or keyword followed by a. and/And what is different is that when you use/find the keyword, by pressing the N key to find the next keyword, the n key means to find the previous keyword. It's the opposite, and it's fun to try it.

And when we turn the page, we see some English boldface capitals in the man document, what are they?

Take man man for example.

1 name is the name of the command, as its name implies

2SYNOPSIS is the gist of the order.

3 Description of the DESCRIPTION command

4 chapters of the MANUAL sections manual there are some commands.

5ENVIRONMENT Environment

6BUG Bugs!

7AUTHOR author

9SEE also is also suitable for

Wait, anyway. The man command is a powerful command, and if Ken takes some time to translate it into English, it will get different feelings.