Http://wenda.tianya.cn/wenda/thread?tid=1d4b0f172f958833Linux operating system--help, man, and info tools
The Linux operating system provides us with a very convenient system documentation help information. Examples include the "--help" option, the Man tool, and the Info tool documentation. Many beginners are not very familiar with the concept of these three kinds of help information, so let's make some pertinent explanations.
[b] "--help" option [/b]
"--help" is a tool option, and most GNU tools have this option, and the "--help" option can be used to display information about some tools, such as typing in the command line:
$ fdisk--help
The following information is displayed:
[Img]http://linux.ccidnet.com/col/attachment/2007/11/1302331.jpg[/img]
[b] "man" tool [/b]
The man tool can display the contents of the System man page, most of which is an explanation of the command. By looking at the man page in the system documentation, you can get more information about the topic of the program and more features of Linux. Man is a very useful tool, and when you are using a command that is unfamiliar to you, the man command can be very helpful.
When you need to know more detailed information about a tool, you can do so by using the command man followed by the tool name.
As in the command line, type:
$ man fdisk
The following information is displayed:
[Img]http://linux.ccidnet.com/col/attachment/2007/11/1302333.jpg[/img]
Press the space key to display the next screen of text information, press the Q key will exit man and return to the shell prompt. You can also use PageUp and pagedown to scroll through.
[b] "info" display tool information [/b]
The Info tool is a menu-based hypertext system developed by the GNU Project and released by Linux. The Info tool includes some documentation about the Linux shell, tools, and GNU Project Development Program.
As in the command line, type:
$ info fdisk
The following information is displayed:
[Img]http://linux.ccidnet.com/col/attachment/2007/11/1302335.jpg[/img]
(The information above is from an editable file, and different versions of Linux may show different results.) ）
When the above information is present:
Press down? Key, you can list the relevant commands in the Info window.
You can scroll through the menu item by pressing the SPACE key.
[b] Comparison of the three: [/b]
The "--help" option is not a "standalone" tool. As a command option, it can be used to modify the way a tool or command works. The options for a command are usually specified by one or two hyphens followed by one or more letters. The option is separated by a space after the name of the tool being called. The other parameters of the tool are followed by the options and are separated by a space. The "--help" option is like a pager "| Less ", it provides a quick and efficient help.
Man and info are like two collections, they have an intersection section, but compared with man, the info tool displays more complete and up-to-date GNU tool information. If the man page contains an overview of a tool that is also described in info, then the man page will have the words "please refer to info page for more details". Typically, the man tool displays information that is unique to the non-GNU tool, and the Info tool displays a copy of the non-GNU tool that complements the content of the man page.
Linux operating system--help, man, and info tools for different introduction
