Malta Linux User Group

A "shell" is a program which interprets commands, either typed in directly by the user, or contained in a file called a "shell script", which is a simple interpreted program. The equivalents in Windows^TM would be "command processor" for shell, "COMMAND.COM" or "CMD.EXE" instead of bash, and ".BAT files" instead of shell scripts.

Linux has a variety of different shells, but certainly the most popular is "bash", so it is this one which will be described here (even though many of these instructions apply to all shells). Some of the others are retained simply because there are lots of people who got used to them and don’t wish to change, or because they are aimed at a specialised set of users.

Trivia:
Linux, like all unixes, uses a lot of acronyms for its program names, many of them somewhat humorous (eg, yacc="yet another compiler compiler"). Most shells end in "sh", and include ksh (korn shell), csh (C shell... seashell, get it?) and bash (Bourne again shell).

Accessing the terminal

The easiest way to access the terminal, once you have logged in as the new user you created, is to click on the terminal icon from the icon panel at the bottom of the screen, or from the start menu.

The first picture shows KDE’s terminal icon, and the second one shows Gnome’s. The instructions in this document apply to both, since both will load the user’s default shell which is bash. With other GUI’s, look for "xterm" in the menus, or any other program name ending in "term" or "terminal".

Another way of accessing the terminal is to load Linux in text mode. Many servers are configured not to load graphics by default, so the first thing you’d meet is a login prompt in text mode. "Home" or "desktop" computers on the other hand usually start up in graphics mode.

You can try the text-mode prompt easily by pressing Alt-Ctrl-F1to switch to text mode and Alt-Ctrl-F7 to switch back. Actually, from Alt-Ctrl-F1 to Alt-Ctrl-F6 are usually set up as 6 individual text-mode login prompts, while Alt-Ctrl-F7 is the graphics mode.

This picture shows a terminal window - in this case, KDE’s "Konsole".

When you first load the terminal window (or log in from the text-mode login prompt), you will see a prompt somewhat like the above. The actual text within the prompt can be user-defined, and varies between distributions. Generally however, the prompt includes the current username, the name of the computer, and the current directory. Thus in the above picture, the user is "sandbox", the computer is "laptop", and the directory is "~", which is actually short for the home directory.

Entering commands

Throughout this document you will be entering many commands. Each time, type in the words and symbols as given and press Enter (or Return) at the end.

Keep in mind that, as with almost everything else in Linux, the commands are case-sensitive. So, if you’re supposed to type in "ls", typing "LS" won’t work.

Exiting from the terminal

The first thing you might want to know is how to exit. Simply type in "exit" and press Enter, or else press Ctrl-D. The terminal window will quit. Although it is also possible to exit by clicking the "close" button or menu-option, this is the preferred method since it ensures that you are not in a text editor or other application where you could lose data.