19.E: Mode

19: emacs

19.C: Cutting and Pasting

When you are editing a file in emacs, you are not really editing the file itself, but a copy of it which is stored in the computer's memory (and on the disk in files with names like filename~). The copy in memory is also known as a file buffer. Each file has it's own separate buffer and emacs allows you to edit multiple buffers. Emacs uses buffers to allow you to edit multiple files.

The command to start editing another file is the find file command. The find file command is C-x C-f, followed by the filename. If the file doesn't exist, emacs will create a new file for you with that name. Finding a file makes a new buffer inside emacs. Try creating a new buffer by finding your home page.
C-x C-f public-html/index.html

Once you are editing more than one buffer, it is handy to be able to see a list of all the buffers currently active in emacs. The way to do this is C-x C-b. After you enter this command a list of buffers will appear in a split screen. If you wish to switch to a different buffer, you can click on the name with your mouse and then press 1. If you don't have a mouse, use C-x o to switch to the buffer window. Try switching your buffers back and forth.

To get rid of the buffer list type C-x 1. This command tells emacs that you only want to view on window at a time. (This will be covered further in the "Windows" section.) If you already know the file you wish to edit, you have two more options. You can use the find command again or use C-x b filename. (The last buffer used is the default, so if you want that one you can skip the filename.)

If you do make changes to one file, then switch to another file, keep in mind that emacs does not automatically save the first file. The changes only remain in the file's buffer. You can save the buffer you are currently editing with C-x C-s, C-x C-w filename to save the file to a different name, or you can use the command C-x s to save all buffers. If you issue the save all buffers, emacs will then prompt you as to whether to save each particular file.

To exit a buffer without exiting emacs use C-x k to kill the current. This command will warn you if the file has not been saved. If you type this command by accident C-g will save your buffer and bring you back to it.

We have now covered the basic emacs commands. In the next couple of sections, we will be dealing with some convenient commands. Let's start with explaining more about the Mode line.

19.E: Mode

19: emacs

19.C: Cutting and Pasting