ex commands enable you to switch between multiple files. The advantage to editing multiple files is speed. If you are sharing the system with other users, it takes time to exit and reenter vi for each file you want to edit. Staying in the same editing session and traveling between files is not only faster for access, but you also save abbreviations and command sequences that you have defined (see Chapter 7), and you keep yank buffers so that you can copy text from one file to another.
When you first invoke vi, you can name more than one file to edit, and then use ex commands to travel between the files. For example:
$ vi file1 file2
edits file1 first. After you have finished editing the first file, the ex command :w writes (saves) file1 and :n calls in the next file (file2).
Suppose you want to edit two files, practice and note.
|vi practice note||Open the two files practice and note. The first-named file, practice, appears on your screen. Perform any edits.|
|:w||Save the edited file practice with the ex command w. Press RETURN.|
|:n||Call in the next file, note, with the ex command n. Press RETURN. ...|