Here is a list of definitions I've created. Since technology in the computer field changes so fast, many of these may not be found in the computer dictionary you bought from the bookstore. On the other hand, you'll find this list woefully incomplete. Still, I add definitions as needed. If you would like to see a word added, email me.

If you're interested in jargon and computer terms, particularly hacker slang, see Eric Raymond's jargon file.

Console
This is one of the "text-mode" screens you get with Linux. It is similar to the DOS prompt, and there are typically seven consoles available under Linux. This means that you can start doing something on one console, switch to another console to do something else, switch back, etc.

Copyleft
See GPL. This is a hacker's pun on the word copyright.

Cron
Cron is a program (a daemon) that runs in the background on a Linux system, and periodically does tasks you assign to it. Cron "wakes up" every second or so and checks to see if there are any jobs for it to do, and does them. What jobs it does are defined by a crontab files. See man cron, man 1 crontab and man 5 crontab for more complete information.

Daemon
A daemon is any program that runs automatically in the background without you having to be involved. Daemons can be created to clean up temporary files, rebuild manual pages, etc.

Emacs
An editor programmed by Richard Stallman which, unlike vi, is a "modeless" editor. Emacs is incredibly complex compared to many other editors, yet is far more powerful than most other editors. Since emacs is based on a version of the lisp programming language, it is almost infinitely extensible. Thus emacs can be used as a scheduler, email program, game playing environment, or any of a number of other things. Emacs is quite a large program, especially with all the lisp files that come with it. Vi, by contrast is quite small.

Free software
This term is confusing and can mean two things:
  1. free, as in costing nothing, and
  2. free, as in free for your unencumbered use and distribution.
As most people seem to understand the term "free" to be monetarily free, and as this term has often been applied to Linux, it caused confusion. Linux may or may not be commercially free, depending on how you obtained it. Thus, a better term was created, "Open Source". This made clear the type of "free" meant when applying the term to Linux.

Free Software Foundation (FSF)
An effort by Richard Stallman (often referred to as "rms") to promote free software. In this sense, Stallman means both monetarily free, and also free of the licensing encumberances of commercial software. The FSF is responsible for the GNU Project, the GNU Public License, and much of the software that comes with Linux distributions.

GNU
This stands for "GNU's Not Unix". This is a project by the Free Software Foundation to produce a "free" Unix-like environment, in contrast to the commercial (and expensive) Unixes. Most of the basic utilities that come with Linux distributions are GNU utilities-- programs originally appearing under commercial Unixes, but recoded under the GPL. This fact has led Richard Stallman to insist that Linux be called "GNU/Linux", since only the kernel of Linux is truly "Linux".

GNU public license (GPL)
This is a license for software whose provisions chiefly include the following:
  1. You must have access to the source code of the program;
  2. You have to right to modify the source code as you like;
  3. You are free to give away or sell the program;
  4. You may not prevent anyone else from distributing either the original code or your modifications.

GUI
GUI is an acronym for "graphical user interface". This is like Microsoft Windows, with icons, buttons, dialog boxes, etc. Compare console.

Hacker
Contrary to the popular press, a hacker is not a person who breaks into other people's computer systems. That is a cracker. A hacker could be said to be a consummate programmer, someone who has earned the respect of his fellows by programming well or coming up with an elegant way of programming a computer to do a certain job. For programmers, being a hacker is a great honor, and it can only be bestowed upon you by another hacker. Crackers are also often hackers, but their intent and nefarious activities put them into a different category.

Init
Init is the first program that the kernel runs. It cycles through a series of scripts to start various processes running on your machine. Every process on the machine is given a unique process number, and the process number of init is 1.

Kernel
The kernel is the central program of any operating system. This is the program that talks directly to the hardware of the computer. Other programs make requests of the kernel to get something done on the computer. For instance, in order to put a character on the computer screen, a program must ask the kernel to put a certain character in a certain place on the display screen. (There are exceptions to this, but in general, all communication to the computer hardware goes through the kernel.

Open Source
Simply put, this is software which includes source code for your use or modification. Open Source is often released under the GNU Public License, but may be released under similar licenses.

Open Source Software (OSS)
Software that is licensed under an open source license.

Stallman, Richard (rms)
The originator of the Free Software Foundation and programmer of various Unix programs, including Emacs. Stallman's views on software (price and licensing) are quite radical, and he uses any public forum to expound on those views.

Torvalds, Linus
Linus Torvalds is the person who originated and still maintains the Linux kernel. He started this when he was a university student in Finland.

VC
See console

Vi
Vi is a very simple, yet powerful, editor. Unlike emacs, which is a "modeless" editor, vi uses "modes". That is, at any point in an editing session, you may be in insert mode, command mode, etc. While in a certain mode, there are many things you cannot do. You may have to exit the mode you are in, and re-enter a different mode to do those things. While not as powerful as emacs, vi is probably the most universally available editor on all Unix/Linux platforms. Part of the reason for this is its small size.

Virtual Console
See console

X-Window
This is the graphical user interface for Linux. This is a generic name for this. In fact, the X-Window system consists of two parts: the X-Window server and one or more X-Window clients. The server is like the operating system for the clients; they can only get anything done by asking the server to do it. The clients can be anything from spreadsheets to games.

XFree86
This is main open source X-Window server for Linux. There are other X-Window servers, but this is the primary one that ships with Linux distributions.