ex (editor)

ex, short for EXtended, is a line editor for Unix systems.The original ex was an advanced version of the standard Unix editor ed, included in the Berkeley Software Distribution. ex is similar to ed, with the exception that some switches and options are modified so that they are more user-friendly.ex was eventually given a screen oriented visual interface (adding to its command line oriented operation), thereby becoming the vi text editor. In recent times, ex is implemented as a personality of the vi program; most variants of vi still have an "ex mode", which is invoked using the command ex, or from within vi for one command by typing the : (colon) character. Although there is overlap between ex and vi functionality, some things can only be done with ex commands, so it remains useful when using vi.
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