Now that you have come across configuration files, we want to give you at least a small head start on how to edit them. We save the real discussion of various text editors for Chapter 19.
We use the Emacs editor as an example here because it is both widely available and fairly user-friendly. Other editors, such as vi, are even more widely available, but not very user-friendly for a beginner. Again, others are more user-friendly, but may not be available on your Linux installation. We talk more about vi and the other editors later.
Emacs comes in two different incarnations: GNU Emacs and XEmacs . GNU Emacs is started by issuing:
$ emacs filename
and XEmacs is started with:
$ xemacs filename
If you are not running from a graphical environment, add the -nw option (for "no windows"):
$ xemacs -nw filename
It is very likely that either GNU Emacs or XEmacs is available on your installation, and for the simple things we are going to do now, the differences do not matter. If you have both at your disposal, we would personally recommend XEmacs.
At this point, there are only very few things you need to know: how to enter and edit text, how to save your edits, and how to terminate the editor. Of course, Emacs can do many more advanced things, but we'll save those for later.
When you have started Emacs, you will see the file you specified on the command line loaded into its buffer. You can freely type away, edit, enter new text, delete existing text using the Backspace key, and move around with the cursor keys. When you want to save your file, you use the key combination C-x C-s. This is Emacs jargon for "hold down the Control key, press the X key, release both, hold down the Control key, press the S key, release both." This may sound arcane to you, but when you have done this a couple of times, you will have the combination "in your fingers" and will not even think about it. Some Emacs installations even come with graphical menus like you may be used to from other operating systems, but these are not universally available, so we stick to what is guaranteed to be there for now.
When you are done with your edits and have saved your file, you will probably want to leave Emacs. This is done with the key combination C-x C-c. You can probably guess it by now: this means "hold down the Control key, press the X key, release both, hold down the Control key, press the C key, release both." This will get you back to the command line.