Linux Learning notes Three ———— overview of Linux commands

First, Introduction

• Many people may have seen similar scenes on TV or in movies, and hackers face a black screen with dense characters and bang-bang knocks to complete the task of stealing data.
• When Linux was born, there was no graphical interface, and all operations were done by command, just as the hackers on TV were full of mystery and obscurity.
• In recent years, although Linux has developed very quickly and the graphical interface is becoming more and more friendly, the application of the Linux command line occupies a very important place in the real development process, and many Linux functions run faster than the graphical interface in the command line interface. You can say no to the command line, it does not count Linux.
• Linux provides a large number of commands, which can be used to do a lot of work effectively, such as disk operations, file access, directory operations, process management, file permission settings and so on. The minimum number of commands for Linux distributions is also more than 200, which only describes the more important and most frequently used commands.

II. Overview of Linux commands

1. How to use the command

<1>linux command format:

    command  [-options]  [parameter1]  …

Description

• Command: Name, corresponding function of the English word or word abbreviation [-options]: options, can be used to control the command, can also be omitted, []代表可选 parameter1 ... : Parameters passed to the command: can be 0 one or more

<2> Example:

2. View the Help document

<1>--help

Usually the Linux command comes with help information

such as: LS--help

<2>man (Problem finding man, manual)

Man is a handbook provided by Linux that contains most of the commands, function instructions

The manual is divided into chapters (sections), which can be used to specify different chapters to browse using man.

Example: Man ls; Mans 2 printf

The meanings of each section in man are as follows:

1. Standard commands (normal command)
2. System calls (systems calls, such as Open,write)
3. Library functions (libraries functions, such as Printf,fopen)
4. Special devices (description of the device file, various devices under/dev)
5. File formats (files format, such as passwd)
6. Games and toys (gaming and entertainment)
7. Miscellaneous (Miscellaneous, conventions and agreements, such as Linux file systems, network protocols, ASCII codes; environ global variables)
8. Administrative Commands (administrator commands, such as Ifconfig)

Man is searched in the order of chapter numbers in the manual.

The man set the following function keys:

function keys	function
Space key	Show the next screen of the man page
Enter key	One row of the scroll manual page
B	Roll back one screen
F	Roll forward one screen
Q	Exit Man command
H	List all function keys
/word	Search Word string

Note: In fact, we do not need to specify the section of the chapter is also used to view, such as, man LS

3. Auto-Complete: tab

At the same time as the first few letters of the command, pressing the TAB key, the system will automatically help us complete the command

4. Historical command: History

After the system has executed some commands, you can press the up and down keys to look at the previous command, the history of the executed commands listed

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Source: Organize from Network

Linux Learning notes Three ———— overview of Linux commands