6. Entering and Exiting Emacs

The usual way to invoke Emacs is with the shell command emacs. Emacs clears the screen, then displays an initial help message and copyright notice. Some operating systems discard your type-ahead when Emacs starts up; they give Emacs no way to prevent this. On those systems, wait for Emacs to clear the screen before you start typing.

From a shell window under the X Window System, run Emacs in the background with emacs&. This way, Emacs won't tie up the shell window, so you can use it to run other shell commands while Emacs is running. You can type Emacs commands as soon as you direct your keyboard input to an Emacs frame.

When Emacs starts up, it creates a buffer named ‘*scratch*’. That's the buffer you start out in. The ‘*scratch*’ buffer uses Lisp Interaction mode; you can use it to type Lisp expressions and evaluate them. You can also ignore that capability and just write notes there. You can specify a different major mode for this buffer by setting the variable initial-major-mode in your init file. Voir la section The Init File, ‘~/.emacs’.

It is possible to specify files to be visited, Lisp files to be loaded, and functions to be called through Emacs command-line arguments. Voir la section Command Line Arguments for Emacs Invocation. The feature exists mainly for compatibility with other editors, and for scripts.

Many editors are designed to edit one file. When done with that file, you exit the editor. The next time you want to edit a file, you must start the editor again. Working this way, it is convenient to use a command-line argument to say which file to edit.

However, killing Emacs after editing one each and starting it afresh for the next file is both unnecessary and harmful, since it denies you the full power of Emacs. Emacs can visit more than one file in a single editing session, and that is the right way to use it. Exiting the Emacs session loses valuable accumulated context, such as the kill ring, registers, undo history, and mark ring. These features are useful for operating on multiple files, or even continuing to edit one file. If you kill Emacs after each file, you don't take advantage of them.

The recommended way to use GNU Emacs is to start it only once, just after you log in, and do all your editing in the same Emacs session. Each time you edit a file, you visit it with the existing Emacs, which eventually has many files in it ready for editing. Usually you do not kill Emacs until you are about to log out. Voir la section File Handling, for more information on visiting more than one file.

To edit a file from another program while Emacs is running, you can use the emacsclient helper program to open a file in the already running Emacs. @xref{Emacs Server}.

Ce document a été généré par Eric Reinbold le 23 Février 2009 en utilisant texi2html 1.78.