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 Chapter13 as part of our discussion of the right size of software.

As we noted in Chapter13, 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.