ex, short for EXtended, was a line editor for UNIX. It was an advanced version of the standard UNIX editor ed, included in the Berkeley Software Distribution. Eventually, ex was given a Visual Interface, thereby becoming vi. Most versions of vi still have an "ex mode", and this mode can be invoked on most UNIX-like systems using the command "ex". A line editor is a text editor computer program that is oriented around lines. ... UNIX® (or Unix) is a portable, multi-task and multi-user computer operating system originally developed by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... For an overview of letters that look similar to Ð see Ð (disambiguation) Ð (capital Ð, lower-case ð) (or eth, eð or edh, Faroese: edd) is a letter used in Old English (Anglo-Saxon) and present-day Icelandic and Faroese. ... BSD redirects here; for other uses see BSD (disambiguation). ... vi is a screen-oriented text editor computer program written by Bill Joy in 1976 for an early BSD release. ... Mode has several meanings: In statistics, the mode is the value that has the largest number of observations, namely the most frequent value or values. ...