shello is short for "shell logo".
It helps you configure a shell logo for your bash shell so that you don't forget on which machine you're working on.
All you need to do is download shello.sh, do a "chmod +x shello.sh" and run "./shello.sh" and complete the instructions it provides.
Hmm, what else can I say... patches welcome?
Shello is also "An extremely casual and almost lazy way of greeting someone.":
Shellos are a type of water Pokémon: