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2.8 Keyboard
Habits
In this chapter we have seen that bash provides command-line editing with two modes: vi and emacs. You may
be wondering why these two editors were chosen. The primary reason is because vi and emacs are the
most widely used editors for UNIX. People who have used either editor will find
familiar editing facilities.If you are not familiar with either of these
editors, you should seriously consider adopting emacs-mode keyboard habits. Because
it is based on control keys and doesn't require you to think in terms of a
"command mode" and "insert mode," you will find emacs-mode
easier to assimilate. Although the full emacs
is an extremely powerful editor, its command structure lends itself very well
to small subsetting: there are several "mini-emacs" editors floating
around for UNIX, MS-DOS, and other systems.The same cannot be said for vi, because its command structure is really meant for
use in a full-screen editor. vi is quite
powerful too, in its way, but its power becomes evident only when it is used
for purposes similar to that for which it was designed: editing source code in
C and LISP. As mentioned earlier, a vi user has
the power to move mountains in few keystrokesbut at the cost of being unable
to do anything meaningful in very few keystrokes. Unfortunately, the latter is
most desired in a command interpreter, especially nowadays when users are
spending more time within applications and less time working with the shell. In
short, if you don't already know vi, you will
probably find its commands obscure and confusing.Both bash
editing modes have quite a few commands; you will undoubtedly develop keyboard
habits that include just a few of them. If you use emacs-mode and you aren't
familiar with the full emacs, here is a subset
that is easy to learn yet enables you to do just about anything:
For cursor motion around a command line, stick
to CTRL-A and CTRL-E for beginning and end of line, and CTRL-F and CTRL-B for
moving around.
Delete using DEL (or whatever your
"erase" key is) and CTRL-D; as with CTRL-F and CTRL-B, hold down to
repeat if necessary. Use CTRL-K to erase the entire line.
Use CTRL-P and CTRL-N (or the up and down arrow
keys) to move through the command history.
Use CTRL-R to search for a command you need to
run again.
Use TAB for filename completion.After a few hours spent learning these
keystrokes, you will wonder how you ever got along without command-line editing.
