In this module, we will continue our discussions about the Linux Operating system with a discussion of Linux ‘man pages’. The Linux man pages are the most popular method of obtaining help about how to run commands.
At the conclusion of this module, we hope you will have a better understanding of how to obtain information when using the command line interface. At the end of this session, you will be able to:
Recognize the typical manual format
Use the `man` command
Search through the available corpus of text
Find other resources for Linux help
The first unix system was built in 1969. As is typical of computer scientists, no documentation for the new system existed until 1971, and then only at the request of management.
Man is a abbreviation of the word ‘manual’, and provides a method for learning about the commands that exist within the system.
To use man, type man, then a space, and then the command you want to learn more about. You can see that the format is simple and easy to read.
Navigation within the man pages is handled by the arrow keys on your keyboard.
Pressing the down arrow will scroll the page down one line, allowing you to read more of the page.
Conversely, pressing the up arrow scrolls the page up one line.
To exit out of the man page, simply press the ‘q’ key on your keyboard.
Each man page is written by the author of the command. Because of this, each man page can have different headings, but many follow a standard format that includes the following information:
The name of the command
A short synopsis of how the command is used. There are a few idiosyncrasies about the Synopsis: o Anything in square brackets is not required to be included o Whenever you see an ellipsis – three dots or periods in succession – the previous option can be used any number of times
A description of what the command does, or what output you can expect, and a listing of all available options. o Command line options, when they are used in conjunction with the program, will typically
Alter the behavior of the command as it is
Alter the output of the command by expanding, or truncating the output
Examples of how to use the command and what output, or behavior, you can expect from it
A listing of similar, or closely related, commands for which you can then read the manual.
You can use the ‘-k’ flag appended to the man command to search thorough a database of man pages.
This can be useful to find commands that are similar in function to the original.
You can also search the full text of the man page by
pressing the forward-slash (‘/’), typing the word for which you want to search, then pressing enter. This should highlight the search term within the man page.
After you have searched for the string, you can press the ‘n’ and ‘p’ keys to proceed to the next, or previous, instance of the search term.
No discussion of Linux help pages would be complete without mentioning the variety of resources that are available in other locations.
There is an online repository of manual pages at the kernel.org website, which can be extremely useful to reference while using the command line
Google, or any other search engine, can provide a wealth of information on any particular topic.
Lynda.com is an online repository of tutorials and videos that has an extensive selection of tutorials on the Linux Operating System.
When using a new system, it is very important to have the ability to access relevant documentation on its purpose and function. The Linux manual pages provide ample coverage, but can be easily supplemented by some great online resources.
In this video, we have covered several different ways of obtaining more information about specific unix commands, including:
Using the ‘man’ command; Searching through the manual database using ‘man –k’;
Searching through the actual man pages with the forward-slash (‘/’); and
Locating other online resources for supplemental material.
We recommend that you understand the material presented here before continuing with the next videos. See you next time.