Questions about the text editor "vi"
"Vi" is a screen-oriented text editor originally created for the Unix operating system.
The portable subset of the behaviour of vi and programs based on it, and the ex editor language supported within these programs, is described by (and thus standardised by) the Single Unix Specification and POSIX.
The name vi is derived from the shortest unambiguous abbreviation for the command visual in ex; the command in question switches the line editor ex to visual mode.
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