Vi
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 Vi facts

• The portable subset of the behavior of vi and programs based on it, and the ex editor language supported within these programs, is described by (and thus standardized by) the Single Unix Specification and POSIX
• The original code for vi was written by Bill Joy in 1976, as the visual mode for a line editor called ex that Joy had written with Chuck Haley
• Bill Joy's ex 1
• 1 was released as part of the first BSD Unix release in March, 1978
• It was not until version 2
• 0 of ex, released as part of Second Berkeley Software Distribution in May, 1979 that the editor was installed under the name "vi" (which took users straight into ex's visual mode), and the name by which it is known today
• Some current implementations of vi can trace their source code ancestry to Bill Joy; others are completely new, largely compatible reimplementations
• The name "vi" is derived from the shortest unambiguous abbreviation for the ex command visual, which switches the ex line editor to visual mode
• The name vi is pronounced /ˈviːˈaɪ/ (as in the discrete English letters v and i)
• In addition to various non–free software variants of vi distributed with proprietary implementations of Unix, vi was opensourced with OpenSolaris and several free and open source software vi clones exist