The Shell

One of the best things about the Amiga is its versatility. While the rest of the personal computing community continues to argue about the best type of interface, Amiga users have both - a graphic interface with Workbench and a text-based interface with the Shell.

The Shell (also known as the Command Line Interface or CLI) preserves the best features of operating computers the "old-fashioned way", that is, by typing commands at a console. Although that is in some ways more difficult than clicking on graphics with a mouse, it provides a finer level of control, less overhead and greater power than is possible through a GUI.

Virtually anything that can be done through Workbench can also be done through the Shell. On Workbench, for instance, a user can move into a subdirectory by double-clicking on its drawer icon. The equivalent of this in the Shell is to type

cd <subdirectory name>

The command dir will then list the contents of the directory.

Your application should support all three interfaces built into the Amiga: the GUI, the Shell and ARexx.

The same example can be used to illustrate the greater power of the Shell. In addition to dir, which gives a brief listing of files and subdirectories, the user can also use list which gives a more in-depth listing including the size of each file, information about the file and when it was last updated. Or you could list only a subset of files by using wildcards in the command. For example,

list #?.info

would list only those files ending with ".info".

The Shell
Fig. 8.1: The Shell

In addition to being able to do things with finer control than Workbench, the Shell can also do some things that Workbench cannot do at all. For instance, from the Shell you can create a script - a pre-recorded set of commands that helps to automate repetitive tasks.