Vim or Vi Improved is an early text editor based on the Vi that was commonly used on systems with Unix like features. It was designed to be used on both command line interface and GUI systems. It is an open source program, and similar to its predecessor the interface is based on commands in a text UI instead of having icons or menus.
Vim has a GUI mode known as gVim, which is featured with menus for more commonly used commands. However, the main functions can be used only through the command line mode.
One of the strengths of Vim is that it is highly customizable. It is possible for users to control the interface using many options. It is also possible to define custom key mappings, referred to as macros for automating keystroke sequences or for calling user defined or internal functions.
XEmacs is a customizable, open source text editor. Its scheme is somewhat like Linux – closer to modern GUI support and open application development. It can run on all Unix versions, Linux and Windows 95/NT. The text editor has been provided support by many organizations and academic institutions, and there is a large development community.
Emacs, XEmacs predecessor was a highly popular editor. A typical text editor comes with functionalities pre-determined by the author, but with Emacs you could do almost anything. For example, if you wanted to write a program for reading email in Emacs, it can support POP, IMAP, MIME, SSL and much more. It can support almost everything that is found in a mail program. Many such other features made the Emacs much more than a text editor, the reason why it became so popular.
GNU Emacs is the most popular version of the text editor. There are more than a couple thousand built-in commands in this editor. You can also combine the commands to create macros for automating tasks. Although GNU Emacs was developed in the 1970s it still continues to be in operation.