Common Linux commands (version 2)-Help commands

Common Linux commands (version 2)-Help commands
Help commands

1. man [manual]:/usr/bin/man

Obtain the help document of the command or configuration file, and check the help of the command first.

Format: man [command or configuration file] # Call more

E. g.

Man ls # view the help information of the ls command

Man services # view the help information of the configuration file services

Appendix-there are nine types of help files in Linux:

For example, man 5 passwd // view the help of the configuration file

Default Value: man 1 passwd

2. info [information]:/usr/bin/info

Note: There is no big difference with man, except that the information is not presented in the same way, and this command is not available in UNIX systems.

3. Get brief information about the relevant file:

1) whatis [search the whatis database for complete words.]

Format: whatis [any keyword]

# Obtain the brief description of the index and find the basic purpose of this command.

For example, whatis apropos

2) apropos [search the whatis database for strings.]

Format: apropos [any keyword]

# Used to obtain file configuration information, similar to: man-k [file]

Appendix-but to run these two commands correctly, you must create a whatis database. The command must be run as root.

/Usr/sbin/makewhatis

# If an error occurs when these two commands are used, the whatis database is not created.

Appendix-[command] -- help # mainly used to obtain command option Information

Apropos [file]

4. help # view the file help of Shell built-in commands

For example, the difference between man cd and help cd

Appendix-man bash # used to view built-in commands contained in Shell

For more information about Shell, see other blogs-four days proficient in Shell programming series:

Http://blog.csdn.net/zjf280441589/article/details/17455515

Http://blog.csdn.net/zjf280441589/article/details/17467069

Http://blog.csdn.net/zjf280441589/article/details/17487351

Http://blog.csdn.net/zjf280441589/article/details/17503985