Java™ Application Development on Linux - Dator

34Chapter 2An Embarrassment of Riches: Editors2.2EYE TO EYE WITH VIJava programs consist of Java classes. Java classes are text files with Java statementsand expressions. In order to write a Java program, then, you need to beable to enter text into a file. Sounds simple enough.With Linux and its GNU tools, you have an amazing array of choices forhow to do this. Some are GUI tools not unlike simple word processors. Others,like vi and Emacs, predate GUI tools, but provide much the same capabilitywithout the luxury (or annoyance) of a mouse or menus. 1The editor named vi (pronounced as you would spell it: “vee-eye”) is oneof the most enduring tools in Linux. Its popularity comes from a combinationof power and ubiquity—you can find it on virtually every release of UNIX andLinux since 1985. But it is a powerful editor that can do a lot with only a fewkeystrokes.There are actually several variants of vi from which to choose. Each issomeone’s attempt to go one better on vi, but all retain the same basic syntaxand what you learn here will work equally well on any of the vi clones. You canchoose among• elvis• nvi• vimStart up vi by typing the command name at a shell prompt, followed bythe name of the file(s) that you want to edit:$ vi Account.javaKeep in mind that vi was developed in the days of character-only videoscreens. Keyboards didn’t always have arrow keys or other special characters,which have since been (largely) standardized by the advent of the IBM PC. Inthat situation, the authors of vi had only the alphabetic characters to use for all1. We realize that vi is famous for being difficult to learn and nonintuitive. The UI design ofvi dates back to earliest cursor-addressable display terminals. User interface design has come along way since then. The vi UI does indeed show its age. But the program refuses to die. Why?Because while simple GUI editors make the easy stuff easy, vi makes the hard stuff easy. Youcan fall back on pico or kate or other GUI editors if you want, but bear with us. Mastering vireally does pay off.