A text editor is a type of program used for editing plain text files. Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code.
Some text editors are small and simple, while others offer a broad and complex range of functionality. For example, UNIX and Unix-like operating systems have the VI editor (or a variant), but many also include the Emacs editor. Microsoft Windows systems come with the very simple Notepad, though many people—especially programmers—prefer to use a text editor with more features. Under Apple Macintosh's classic Mac OS there was the native SimpleText, which was replaced by Text Edit. Some editors, such as WordStar, have dual operating modes allowing them to be either a text editor or a word processor.
Text editors geared for professional computer users place no limit on the size of the file being opened. In particular, they start quickly even when editing large files, and are capable of editing files that are too large to fit the computer's main memory. Simpler text editors often just read files into an array in RAM. On larger files this is a slow process, and very large files often do not fit.
Types of Text Editor
Source code editors are text editors with additional functionality to facilitate the production of source code. These often feature user-programmable syntax highlighting, and coding tools or keyboard macros.
Folding editors. This subclass includes so-called "orthodox editors" that are derivatives of Xedit. The specialized version of folding is usually called outlining.
World Wide Web programmers are offered a variety of text editors dedicated to the task of web development. These create the plain text files that deliver web pages.
Integrated Development Environment (IDE) which consists of editor along with other tools like debugger , compiler run time environment, testing component
and many more.