Get Linux Help commands

Classification of commands

Linux commands are divided into internal commands and external commands.
?? An internal command is a command that comes with a shell program that is part of the shell program that is identified by the shell program and runs inside the shell, typically loaded and homed in the system memory when the Linux system loads and runs.
?? An external command refers to a script file or binary program in a Linux system that is capable of accomplishing a particular function, and each external command corresponds to a file in the system and is a command other than the Shell interpreter program, so called an external command. The Linux system must know the file location of the external command before it can be loaded and executed by the shell.

Internal command Get Help

Help COMMAND

External command Get help

1. Commands to bring the use of a brief format help    #COMMAND--help2. User manual: Manual    Location:/usr/share/man    #man COMMAND section            NAME: Functional Description            Synopsis: Syntax format                []: Indicates optional content                <>: Content that must be provided                a| B: Multiple choice ...                : Indicates that similar content can appear multiple times            DESCRIPTION: Description            options: Option            EXAMPLES: using example            AUTHOR: Author            BUGS: How to Report program Bugs            See ALSO: Refer    to the 3.info command's online documentation for commands, as a supplemental document for the Man Handbook 4. The program comes with help documentation:/usr/share/doc/app-version    README: Information    about the program Install: Installation help    changes: Changes to version iterations 5. Official documentation for mainstream distribution 6. Official documentation of the program

• Man Introduction

User manual, compressed format files, with chapters

Section Description:    1. User Commands    2. System call    3.C Library call    4. device files and special text:    5. File format (configuration file format)    6. Game Use Help    7. Miscellaneous    8. Management tools and daemons not every COMMAND has a manual in all chapters, and the default is to find    Whatis COMMAND from the first (see which chapters have manuals)        eg.[ [Email protected] ~]# Whatis passwd           sslpasswd (1SSL)     -compute password hashes           passwd (1)           -Update Us Er ' s authentication tokens           passwd (5)           -Password file               Note: The review process is done by querying the database and executing the makewhatis command to update the database    View the specified section man    # COMMAND Specifies the location of the man    manual find    man-m/path

How to operate the man command after opening the manual

Flip screen:    blank: To the end of the file to turn a screen B: To file the    first screen    ctrl+d: To the end of the file half screen    ctrl+u: to the file header half-screen return    : The end of the file to turn a line    K: Turn the file header into    a line G: Jump to the last line of the file    #G: Jump to # line text search:    /keyword: From the file header to the end of the file to find, not case-sensitive    ? Keyword: Look up from the end of the file to the file header, case-insensitive        N: Same as the direction of the Find command turn        N: Reverses the direction of the search command        exit:    q:quit

Get Linux Help commands