8.5 Files

The commands described above are sufficient for creating and altering text in an Emacs buffer; the more advanced Emacs commands just make things easier. But to keep any text permanently you must put it in a file. Files are named units of text which are stored by the operating system for you to retrieve later by name. To look at or use the contents of a file in any way, including editing the file with Emacs, you must specify the file name.

Consider a file named /usr/rms/foo.c. In Emacs, to begin editing this file, type

     C-x C-f /usr/rms/foo.c <RET>

Here the file name is given as an argument to the command C-x C-f (find-file). That command uses the minibuffer to read the argument, and you type <RET> to terminate the argument (see Minibuffer).

Emacs obeys the command by visiting the file: creating a buffer, copying the contents of the file into the buffer, and then displaying the buffer for you to edit. If you alter the text, you can save the new text in the file by typing C-x C-s (save-buffer). This makes the changes permanent by copying the altered buffer contents back into the file /usr/rms/foo.c. Until you save, the changes exist only inside Emacs, and the file foo.c is unaltered.

To create a file, just visit the file with C-x C-f as if it already existed. This creates an empty buffer in which you can insert the text you want to put in the file. The file is actually created when you save this buffer with C-x C-s.

Of course, there is a lot more to learn about using files. See Files.