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The first and most basic tool of development is a text editor suitable for modifying and writing programs.
Literally dozens of text editors are available under Unix; writing one seems to be one of the standard finger exercises for budding open-source hackers. Most of these are ephemera, not suitable for extended use by anyone other than their authors. A few are emulations of non-Unix editors, useful as transition aids for programmers used to other operating systems. You can browse through a wide variety at SourceForge or ibiblio or any other major open-source archive.
For serious editing work, two editors completely dominate the Unix programming scene. Each is available in a couple of minor variant implementations, but has a standard version you can rely on finding on any modern Unix system. These two editors are vi and Emacs. We discussed them in Chapter═13 as part of our discussion of the right size of software.
As we noted in Chapter═13, these two editors express sharply contrasting design philosophies, but both are extremely popular and command great loyalty from identifiable core user populations. Surveys of Unix programmers consistently indicate about a 50/50 split between them, with all other editors barely registering.
In our earlier examinations of vi and Emacs, we were primarily concerned with their optional complexity and the surrounding design-philosophy issues. Many other things are worth knowing about these editors, both as a matter of practicality and of Unix cultural literacy.
The name of vi is an abbreviation for “visual editor” and is pronounced /vee eye/ (not /vie/ and definitely not /siks/!).
vi was not quite the earliest screen-oriented editor; that palm goes to the Rand editor, re, that ran on Version 6 Unix in the 1970s. But vi is the longest-lived screen-oriented editor built for Unix that is still in use, and is a hallowed part of Unix tradition.
Emacs stands for ‘EDiting MACroS’ (pronounce it /ee╢╥maks/). It was originally written in the late 1970s as a set of macros in an editor called TECO, then reimplemented several times in different ways. In an amusing twist, modern Emacs implementations include a TECO emulation mode.
In our earlier discussion of editors and optional complexity, we noted that many people consider Emacs excessively heavyweight. However, investing the time to learn it can yield rich rewards in productivity. Emacs supports many powerful editing modes that offer help with the syntax of various programming languages and markups. We'll see later in this chapter how Emacs can be used in combination with other development tools to give capabilities comparable to (and in many ways surpassing) those of conventional IDEs.
The standard Emacs, universally available on modern Unixes, is GNU Emacs; this is what generally runs if you type emacs to a Unix shell prompt. GNU Emacs sources and documentation are available at the Free Software Foundation archive site.
The only major variant is called XEmacs; it has a better X interface but otherwise quite similar capabilities (it forked from Emacs 19). XEmacs has a home page. Emacs (and Emacs Lisp) is universally available under modern Unixes. It has been ported to MS-DOS (where it works poorly) and Windows 95 and NT (where it is said to work reasonably well).
Emacs includes its own interactive tutorial and very complete on-line documentation; you'll find instructions on how to invoke both on the default Emacs startup screen. A good introduction on paper is Learning GNU Emacs [Cameron].
The keystroke commands used in the Unix ports of Netscape/Mozilla and Internet Explorer text windows (in forms and the mailer) are copied from the stock Emacs bindings for basic text editing. These bindings are the closest thing to a cross-platform standard for editor keystrokes.
Many people who regularly use both vi and Emacs tend to use them for different things, and find it valuable to know both.
In general, vi is best for small jobs — quick replies to mail, simple tweaks to system configuration, and the like. It is especially useful when you're using a new system (or a remote one over a network) and don't have your Emacs customization files handy.
Emacs comes into its own for extended editing sessions in which you have to handle complex tasks, modify multiple files, and use results from other programs during the session. For programmers using X on their console (which is typical on modern Unixes), it's normal to start up Emacs shortly after login time in a large window and leave it running forever, possibly visiting dozens of files and even running programs in multiple Emacs subwindows.
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