How to ask for help inside Linux

When we are having problems with Linux, we seek help primarily in three ways: Help,what Is,man

A. Help

1. Function : Help command • Used to display a summary of usage and a list of parameters that can be used to view the usage of most commands

2. Usage : Before using the help command we first need to know a concept, what is an internal command what is an external command

internal Command : In order to improve the efficiency of the system, Linux system will often use a lightweight command to load these commands into memory for the shell to invoke at any time when the system starts, which is an internal command. Internal commands are mostly common commands.

External command: The heavier command called by the system layer is the external command, which is stored on the hard disk only when the hard drive is called to load this part of the command

For this we can use the type command to see if a command is an internal command

The help command needs to be called in different ways when viewing internal and external commands

Use "Help + commands" for internal commands to view directly

Here the CD command is mkdir for internal commands and for external commands

Example: Using the Help command to view the use of the internal Command CD command

For external commands we can view them in "command--help"

Example: Using Help to view external command mkdir usage

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3. Advantages and Disadvantages:help can be more clear query the command information we need, although the information is not comprehensive but the general situation can meet our needs, but not all commands support the Help command query

Two. Whatis

1. Function: print the function executed by the target command to the terminal

2. Usage:whatis + command

Example: Querying the CD,PWD command with Whatis

3. Pros and cons : Find Fast, but can only give the function of the target command, and there is no real-time

Three. Man

1. Function:The man command is used to query the official explanation of the target command, which contains information such as the use of the target command, parameters, explanations, configuration files, etc.

2. Usage: The man command actually calls the Linux command manual and divides the commands into nine categories in Linux.

While some commands may span multiple command classes such as the PWD command, they are divided into 1 classes and 3 classes.

Here are some common uses of man

Man command view the first category section of the target command interpretation

The MAN-A command then looks at all the classification chapters of the target command (q exits the section, and then clicks Enter to enter the next section)

man-w command to view the source file of the first classification section to which the target command matches

Man-aw command to view the source files of all the classification chapters to which the target command matches

Man Chapter number command to view the category section of a target command's target chapter

After entering a file in a section of a command, you often see the method:

F Turn down one page

b Turn up one page

G Jump to last page

G Jump to Home

/search keyword n down n up

? Search keyword n up n down

Q Exit Man

3. Pros and Cons: contains all the official interpretations and information of the target command, covering almost all the orders, the most comprehensive, but the interpretation is too official, lengthy

Four. Info

1. Function: View the explanation of the command in the info document

3. Pros and Cons: more friendly and understandable than man, including a number of examples to help understand, but also more lengthy, not conducive to quickly find

How to ask for help inside Linux