vi (pronounced as two letters, / ˌviːˈaɪ / ⓘ) [1] is a screen-oriented text editor originally created for the Unix operating system. The portable subset of the behavior of vi and programs based on it, and the ex editor language supported within these programs, is standardized by the Single Unix Specification and POSIX. [2]
On Unix-like operating systems, vi (pronounced "vee-eye") is a text editor. The vi command starts the visual mode of ex, the landmark editing program developed by William Joy in the late 1970s.
Vim provides both a terminal screen user interface (like vi) as well as a graphical user interface (called gvim). [6] In release information, the author originally implied that Vim was an abbreviation for "Vi IMitation", but later, the expansion was changed to "Vi IMproved".