Working with the Linux Command Prompt
To make Linux commands easy to use, they share a simple, common structure. This section describes their common structure and explains how you can obtain helpful information on the commands available to you.
Command Structure
Linux commands share the common form:
command option(s) argument(s)
The command identifies the command
you want Linux to execute. The name of a Linux command
almost always consists of lowercase letters and
digits. Remember that, unlike Microsoft Windows, Linux is
case sensitive; be sure to type each character of a command
in the proper case.
Most commands let you specify options or arguments. However, in any given case, you may not need to do so. For example, typing the w command without options and arguments causes Linux to display a list of current users.
Options modify the way that a command works. Most options consist of a single letter, prefixed by a dash. Often, you can specify more than one option; when you do so, you separate each option with a space or tab. For example, the –h option of the w command causes the output of the command to omit the header lines that give the time and the names of the fields. Typing:
root@desktop:/root# w -hprints a list of users without the header lines.
Arguments specify filenames or other targets that direct the action of the command. For example, the w command lets you specify a userid as an argument, which causes the command to list only logins that pertain to the specified ...