2.4 INTERMEDIATE CONCEPTS

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Above the basic features of the Linux system are a number of more advanced features and commands. Some of these are listed below.

pine a simple interface for mail usage

mail a somewhat bothersome mail tool (see pine).

man func bring up a manual page for 'func'

man -k string brings up information on 'string'

tar -xvf file.tar extract files from an archive file 'file.tar'

tar cvf - files > file.tar put 'files' into an archive file 'file.tar'

2.4.1 Shells

When one logs into a Linux system, you are actually running a program (shell) this is in some ways similar to DOS. In the standard shell you are given a prompt, where you type your command. If it is not a built-in command, it searches on the disk according to a user-specified search path, for an executable program of that name. Almost all commands are programs that are run in this manner. There are also executable shell scripts, similar to command files on DOS. Linux is limited to running a program of a size equal to the sum of its memory, and swap space. As the system is multi-tasking, any program (or part thereof) that is not currently being run when extra memory is required, is swapped (moved) out to the disk, until it is ready to run again.

In shells there are environment variables set. Some of the commands that can be used to view these are shown below. They can be set by editing the appropriate text files.

alias prints a list of command aliases

printenv prints a list of the environment variables

set prints a list of the environment variables

2.4.2 X-Windows

The GUI in Linux is actually two programs working together. The basic program is called X windows, and it provides basic connection to the screen, mouse, keyboard and sound card. The look-and-feel of the GUI is provided by the window manager. One simple window manager is called `fvwm' and it can behave like Windows 95/98. Newer window managers include Gnome and KDE. While these both provide similar capabilities and features, most users develop personal preferences for a single window manager.

2.4.3 Configuring

Devices and settings can be configured under X-windows using graphical tools. Settings can also be configured with text files, but this is not necessary. Examples of settings that the user or root might want to change are:

Modem properties for internet connection

Network card properties for connection to a LAN

Printer type and location

Customize the windows settings and behavior

Sound card settings and sounds for Window events

2.4.4 Desktop Tools

Most users focus less on the Operating System, and more on the programs that it will run. The task list below includes many of the applications that would be desired by the average user. Most of the listed applications are free, with the exception of the games. Many of these packages are a standard part of Linux distributions.

Office Software - these include spreadsheets, word processors, presentation software, drawing

tools, database tools, 3D graphics tools

Star Office [14]

KOffice [15]

File and Internet Browsers

Netscape - allows browsing of the internet [16]

Files - there are many file viewers that ease directory browsing

Eazel - allows active directory browsing [17]

Administration and Utilities

Apache - the most popular web server program [18]

Postgres and MySQL - Database programs [19] [20]

Replace a microsoft networking server [21]

DOS/Windows Simulator VMWare [22]

Entertainment

Audio and video

Tools (GIMP - similar to photoshop)

Games (Quake, Doom, SimCity)