From Christoph's Personal Wiki
cowsay generates an ASCII picture of a cow saying something provided by the user. If run with no arguments, it accepts standard input, word-wraps the message given at about 40 columns, and prints the cow saying the given message on standard output.
$ echo "Hello, world!" | cowsay $ cowsay -f beavis.zen Hello $ fortune | cowsay $ fortune | cowsay | lolcat $ for i in /usr/share/cowsay/cows/*.cow; do cowsay -f $i "$i"; done # show all cows