Linux Command Line Interface

Linux Command Line Interface

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Online Help / Switches And Conventions

Learning objective: (2) Explain how to use online Help to understand switches and conventions


Click on image to enlarge.

Online help cmd --help

For most commands, adding the switch "--help" will give you access to the core set of switches and other ways to use the command. They are similar to "/?" help switch in MS-DOS. It there mostly to jog your memory of options available with the command.

Switches -x --xxx

In Linux and Unix, the standard switch starts with a "-"dash or "--" double dash. Many switch have a short version like "-v" and a longer switch name like "--version". For ad hoc use, the short switches are fine. When creating scripts, similar to a batch file, using the longer switch name can assist in overall documentation since they are often more descriptive. One of the biggest difference between Linux and DOS are the shear number of switches present in many Linux commands. Remember, switches are case sensitive too. Just because two switches share the same character, they may have no relation to each other like "-h" and "-H".

Options [x]

Just link in DOS, anything inside of square brackets "[ ]" is generally optional.

man cmd (Q to exit, Ctrl+Z to kill)

Man pages (short for manual pages) are the extensive documentation that comes preinstalled with almost all substantial Unix and Unix-like operating systems, except Puppy Linux. The Unix command used to display them is man. Each page is a self-contained document. To read a manual page for a Unix command, one can use 'man cmd' at the command prompt. To exit the manual, press Q key. To kill the manual application, press the Ctrl+Z keys together. [Wikipedia]

✏ Self Quiz!

Select the best response(s) for each question/statement. Use this opportunity to test *your* knowledge and not just move on...

1) In Linux, switches may include...
-switch, like "-v" with a single dash, for short switch names, great for daily use
--switch, "--version" with a double dash, for longer more descriptive names, great for documentation
-help will often display switch options for a command

.

Thinking: How much help is available in Linux? Why?

Key terms: --help, man, options, switch

Resources:
To maximize your learning, please visit these Web sites and review their content to help reinforce the concepts presented in this section.

Quick links:
UNIX For DOS Users
man page @ Wikipedia
Unix/Linux Command Reference (pdf)
Index of Linux Commands
List of Unix utilities @ Wikipedia

Embedded Resources

Notes on navigation: Click inside the frame to navigate the embedded Web page. - Click outside the frame to navigate this page to scroll up/down between the embedded Web pages. - Click on the frame title to open that page in a new tab in most browsers. - Click on the the "Reload page" link to reload the original page for that frame.

UNIX For DOS Users | Reload page | If frame is empty, click on the link to view the page in a new tab or window

man page @ Wikipedia | Reload page | If frame is empty, click on the link to view the page in a new tab or window

Unix/Linux Command Reference (pdf) | Reload page | If frame is empty, click on the link to view the page in a new tab or window

Index of Linux Commands | Reload page | If frame is empty, click on the link to view the page in a new tab or window

List of Unix utilities @ Wikipedia | Reload page | If frame is empty, click on the link to view the page in a new tab or window

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