What is "cowsay"

cowsay is a program which generates ASCII pictures of a cow with a message. It can also generate pictures using pre-made images of other animals, such as Tux the Penguin, the Linux mascot. It is written in Perl. There is also a related program called '''cowthink''', with cows with thought bubbles rather than speech bubbles. .cow files for cowsay exist which are able to produce different variants of "cows", with different kinds of "eyes", and so forth. It is sometimes used on IRC, desktop screenshots, and in software documentation. It is more or less a joke within hacker culture, but has been around long enough that its use is rather widespread. In 2007 it was highlighted as a Debian package of the day.