Vi IMproved, is an open source, multiplatform text editor extended from vi. It was first released by Bram Moolenaar in 1991. Since then, numerous features have been added to Vim, many of which are helpful in editing program source code.
Resources:Nvi is an implementation of the ex/vi text editor originally distributed as part of the Fourth Berkeley Software Distribution (4BSD), by the University of California, Berkeley. The source code to Nvi is freely available, and Nvi may be freely redistributed.
Resources:Emacs is the extensible, customizable, self-documenting real-time display editor. At its core is an interpreter for Emacs Lisp ("elisp", for short), a dialect of the Lisp programming language with extensions to support text editing. Emacs supports graphical user interfaces.
Resources:XEmacs is a highly customizable open source text editor and application development system.
Resources:gedit is the official text editor of the GNOME desktop environment. It is a free software, UTF-8 compatible text editor.
Resources:NEdit is a multi-purpose text editor for the X Window System, which combines a standard, easy to use, graphical user interface with the thorough functionality and stability required by users who edit text eight hours a day. The current stable release of NEdit is version 5.5. NEdit 5.0.2 shipped with Sun Workshop Development Tools.
GNU nano is designed to be a free replacement for the Pico text editor, part of the Pine email suite from The University of Washington. It aims to "emulate Pico as closely as possible and perhaps include extra functionality". Requires ncurses.
Resources:The language-aware editor indents, completes, and syntax-highlights your source code. It parses your code live, matches words and brackets, marks errors, and displays hints and javadoc. The Editor can be fully customized and split vertically or horizontally, and offers well integrated Refactoring, Debugging and JUnit testing.