3, how to use Linux Help

How Linux uses Help

• How Linux uses Help

• which command

• Whatis command

• Use the manual to get help-man command

• View Help with the info command

• Use the software's own help documentation to get help

• Get help with online documentation

• Working with sites and searching

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How Linux uses Help

In Linux there are many commands, configuration files, many command options and parameters that we cannot fully remember, what to do in the work, we can look at the Linux comes with the Help document, or use the search software to search for help

We're going to introduce a concept, Commands in Linux are divided into internal commands and external commands  
internal command : brought by the shell, and provided   in a command form;
external command : There is a corresponding executable file under the current system path

type command to view the command type  
while internal and external commands look for help in different ways

[[email protected] ~]# type  ls  
 ls  is aliased to ' ls --color=auto ' 
 [[email  Protected] ~]# type  pwd  
 pwd  is a shell  builtin   #pwd  shell  built-in command 
  

Example:
Internal command:
help COMMAND
External command:
COMMAND --help
COMMAND -h

which command

which what does this command do for you? We use the command, which is the command to find out whether a system command exists, and where it is executed. Look at the following figure

[root@localhostls
aliasls=‘ls --color=auto‘
    /usr/bin/ls
[root@localhostpwd
/usr/bin/pwd

Whatis command

whatis command is used to query what function a command performs , and print the query results to the terminal.

catman-w command creates a database that looks for commands, system calls, library functions, or special file names that the command parameter specifies. whatis command displays the header line of the manual section. You can then issue the man command to get additional information. The Whatis command equates to the use of man-f command.

ls
lslist directory contents
lslist directory contents
manls

Use the manual to get help-man command

The man command is a help instruction under Linux, which allows you to view information such as instruction help, configuration file Help, and programming help in Linux.

In Linux, the use of man to get help is a pretty good way, it's very detailed and very convenient

The man command is actually a manual that calls the corresponding command in/usr/share/man/[man1-mann], then extracts it to the temp directory and uses less to display it * *

man Chapter

1 :   user command 
 2 :   system call 
 3 : C library call 
 4 :   Device files and special files 
 5 :   configuration file format 
 6 :   Games 
 7 :   Miscellaneous 
 8 :   Commands for managing classes 
 9 : Linux   Kernel API 
  

Help Manual in general follow the relevant format to write, we briefly explain the relevant paragraphs and the role

NAME: Brief description of the name and function of the command
SYSNOPSIS: Brief use of commands help
DESCRIPTION: A brief description of some parameters or options
OPTIONS: Options
AUTHOR: Author
REPORTING BUGS: Address that provides the bug

View Help with the info command

The info command is the Help directive for the Linux info format.

There is a hyperlink stable document, info is an information page that provides the author, Version, when released, etc. more details, man manual is to tell you how to use

[root@localhost ~]# info ls

Use the software's own help documentation to get help

The help documentation that comes with the software in Linux can be found in the/usr/share/doc/software-version/to see if there are redme or install documents to provide relevant help information

Get help with online documentation

Now the command and configuration file on the Internet, there are many versions, for reference, authoritative or official more reliable
Red Hat Knowledge Base and official online documentation
Http://kbase.redhat.com
Http://www.redhat.com/docs
Http://access.redhat.com

Working with sites and searching

http://tldp.org
Http://www.slideshare.net
http://www.google.com
Openstack filetype:pdf
RHCA Site:redhat.com/docs

This article from "Live by the Sea like Waves" blog, please be sure to keep this source http://zhang789.blog.51cto.com/11045979/1845590

3, how to use Linux Help