vi allows you to open files from command mode as well as
specifying a file on the command line to open. To open the file
/etc/lilo.conf:
If you have made changes to the current buffer without saving,
vi will complain. You can still open the file without
saving the current buffer by typing :e!, followed by a
space and the filename. In general, vi's warnings can be
suppressed by following the command with an exclamation mark.
If you want to reopen the current file, you can do so simply by typing
e!. This is useful if you have somehow messed up the
file and want to reopen it.
Some vi clones (for example, vim)
allow for multiple buffers to be open at the same time. For example, to
open up the file 09-vi.sgml in my home directory
while another file was open, I would type:
The new file is displayed on the top half of the screen, and the
old file is displayed in the bottom half of the screen. There are a lot
of commands that manipulate the split screen, and many of these commands
start to resemble something out of EMACS.
The best place to look up these commands would be the man page for your
vi clone. Note that many clones do not support the split-screen idea,
so you might not be able to use it at all.