Print ASCII art (by default a cow) saying or thinking something. More information: https://github.com/tnalpgge/rank-amateur-cowsay.
cowsay "hello, world"
stdin
:echo "hello, world" | cowsay
cowsay -l
cowsay -f art "hello, world"
cowthink -d "I'm just a cow, not a great thinker..."
cowsay -e characters "hello, world"