Focusing on Linux Commands

These days, many important tasks in Linux can be done from both graphical interfaces and from commands. However, the command line has always been, and still remains, the interface of choice for Linux power users.

Graphical user interfaces (GUIs) are meant to be intuitive. With some computer experi- ence, you can probably figure out, for example, how to add a user, change the time and date, and configure a sound card from a GUI. For these cases, we’ll mention which graphical tool you could use for the job. For the following cases, however, you will probably need to rely on the command line:

❑    Almost any time something goes wrong — Ask a question at an online forum to solve some Linux problem you are having and the help you get will almost always come in the form of commands to run. Also, command line tools typically offer much more feedback if there is a problem configuring a device or
accessing files and directories.

❑    Remote systems administration — If you are administering a remote server, you may not have graphical tools available. Although remote GUI access (using X appli- cations or VNC) and web-based administration tools may be available, they usually run more slowly than what you can do from the command line.

❑    Features not supported by GUI — GUI administration tools tend to present the most basic ways of performing a task. More complex operations often require options that are only available from the command line.

❑    GUI is broken or not installed — If no graphical interface is available, or if the installed GUI isn’t working properly, you may be forced to work from the com- mand line. Broken GUIs can happen for lots of reasons, such as when you use a third-party, binary-only driver from NVIDIA or ATI and a kernel upgrade makes the driver incompatible.

The bottom line is that to unlock the full power of your Linux system, you must be able to use shell commands. Thousands of commands are available for Linux to monitor and manage every aspect of your Linux system.

But whether you are a Linux guru or novice, one challenge looms large. How do you remember the most critical commands and options you need, when a command shell might only show you this:

$

NOTE    Most other versions of Linux, as well as Unix, define the default com- mand prompt as a dollar sign, $, (with the root user prompt #). SUSE, however, defines the default command prompt as a greater-than sign (>), but follows the convention of a pound sign (#) for the root user. Throughout this book, you’ll

see $ for the shell prompt for commands that can be run as any user (no special privilege required).

You can change your prompt from the default > by using a command like the following:

>  export  PS1=”[\u@\h  \w]\\$  “ [ericfj@Brodgar  ~]$

This command sets the prompt to your username, @ the current hostname, with

the current working directory, all in square brackets, followed by a more traditional

$ prompt. See Chapter 3 to learn how to set this prompt for all shells by placing

this command inside a bash startup script file.

SUSE Linux Toolbox is not just another command reference or rehash of man pages. Instead, this book presents commands in SUSE Linux by the way you use them. In other words, instead of listing commands alphabetically, we group commands for working with file systems, connecting to networks, and managing processes in their own sections, so you can access commands by what you want to do, not only by how they’re named.

Likewise, we won’t just give you a listing of every option available for every command. Instead, we’ll show you working examples of the most important and useful options to use with each command. From there, we’ll tell you quick ways to find more options, if you need them, from man pages, the info facility, and help options.