Text Editors: vi commands and tips

vi is a family of screen-oriented text editors which share certain characteristics, such as methods of invocation from the operating system command interpreter, and characteristic user interface features. The portable subset of the behavior of vi programs, and the ex editor language supported within these programs, is described by the Single Unix Specification and POSIX.

vi operates in either insert mode (where typed text becomes part of the document) or normal mode (where keystrokes are interpreted as commands). Typing "i" while in normal mode switches the editor to insert mode. Typing "i" again at this point places an "i" in the document. From insert mode, pressing the escape key switches the editor back to normal mode.