Java™ Application Development on Linux - Dator

40Chapter 2An Embarrassment of Riches: EditorsChange does the delete, then puts you in input mode. (Notice the reminderon the status line.) Remember, to get out of input mode and back intovi mode, press the Escape key.Sometimes you’ve done too much, and you’d like to undo what you’vejust done. Typing u will undo the last change that you made. But here’s a differencebetween the classic vi and some of the new, improved versions. In classicvi, if you type another u, then you are telling vi to undo what it justdid—which was an undo. So the undo of an undo remakes the change that youhad originally made. But in vim, “vi improved,” typing u again and again willjust keep undoing previous changes. If you want to undo the undo, in vim,you need to type :redo and then Enter.The vi editor has shortcuts for helping you to change the indentation ofyour code. Typing two less-than signs () will shift the line to the right. Typing a numberfirst and then the less-than or greater-than signs will shift that many lines atonce. But how far will they shift? The default is usually set at eight, but youcan set it to any value you want. In ex mode you can set all sorts of values andflags, customizing vi’s operation. The value we’re interested in here isshiftwidth which can be abbreviated sw. So the command would be :setsw=4 if you want each shift to move by four characters. For more about this,and how to make it your default, see Section 2.2.4.Any command that you do may be worth repeating. Say, you just shifted14 lines and you’d like to shift them further. Or you just deleted five lines, andwould like to delete five more. Well, you could just retype the command, butan easier way is just to type the period (.) and let vi repeat it for you.2.2.1 ExitingThere are three ways of exiting vi (ZZ, :q, :q!) that you should know. Thecorrect one to use depends on whether or not you want to save the changes tothe file and on whether or not you have saved your changes.• ZZ saves and quits in one step (three keystrokes).• :w writes what you’ve been editing but doesn’t quit.• :w filename writes what you’ve been editing to a new file namedfilename; it will complain (and not write out anything) if the filealready exists.