Easter Eggs (Software)

If you’ve been using computers for a long time, you know that an Easter Egg is a small program that is hidden deep inside of an application and is designed by the application’s developers as a way of displaying their names—very similar to the credits that you see at the end of a movie. However, uncovering the Easter Egg is tricky as it almost always involves performing a series of very intricate and non-intuitive steps .Easter eggs can be messages, graphics, sound effects, or an unusual change in program behavior that mainly occur in a software program in response to some undocumented set of commands, mouse clicks, keystrokes or other stimuli intended as a joke or to display program credits. They are often located in the "About" box of a software. An early use of the term Easter egg was to describe a message hidden in the object code of a program as a joke, intended to be found by persons disassembling or browsing the code.
Easter eggs found in some Unix operating systems caused them to respond to the command "make love" with "not war?" and "why" with "why not" (a reference to "The Prisoner" in Berkeley Unix 1977). The TOPS-10 operating system (for the DEC PDP-10 computer) had the "make love" hack before 1971; it included a short, thoughtful pause before the response. This same behavior occurred on the RSTS/E operating system where the command "make" was used to invoke the TECO editor, and TECO would also provide this response.
The largest Easter egg is purported to be in the Atari 400/800 version of Pitfall II: Lost Caverns, which contains an entire game that was more complex and challenging than the original Pitfall II. Many personal computers have much more elaborate eggs hidden in ROM, including lists of the developers' names, political exhortations, snatches of music, and (in one case) images of the entire development team. The 1997 version of Microsoft Excel contained a hidden flight simulator[1][2]; the 1997 version of Word, a pinball game[3]. The Palm operating system has elaborately hidden animations and other surprises. The Debian GNU/Linux package tool apt-get has an Easter egg involving an ASCII cow when variants on "apt-get moo" are typed into the shell. Another notable Easter egg is from The MathWorks' MATLAB: the why command provides succinct random answers to almost any question.