Six ways to get help with Linux commands

One, help Command

Apply to internal commands

Example:

The code is as follows:

# Type cd

CD is a shell builtin

# Help CD

# type LS

LS is aliased to ' LS--color=auto '

# Help LS

-bash:help:no Help topics match ' ls '. Try ' help help ' or ' man-k ls ' or ' info ls '.

　Second, command–help/-h

Applicable to external commands

For example:

The code is as follows:

# ls--help

Three, man Command

Example:

The code is as follows:

# Man CD

Note Manual manual is a chapter; Man # Command (#表示章节号)

1, all users can use the command

2, System kernel calls, not every command has a system call (such as: Man 2 read)

3. Library Call

4, special documents, such as:/dev/tty1

5, file Format (command configuration file syntax, such as: Man 5 passwd)

6. Game related

7. Miscellaneous

8, administrator command, such as: fdisk

The man Command query operation reference to the command mode in "Vi,vim usage"

Read the man command syntax

[]: Optional content

<>: Must give the content

A|b|c: Choose one More

... : You can have multiple

IV. Info Command

There is a hyperlink stability document, info is the information page, provide the author, version, when the release of more detailed information, Man Handbook is to tell you how to use

　　Five, the README

Most programs have a corresponding help document, saved in the/usr/share/doc folder

Such as:

# ls/usr/share/doc/ntp-4.2.4p8/

Changelog COPYRIGHT NEWS

VI, Google

Encounter problems, apart Google, priority reference project official documents