Open your Silica system in the PenguinMod editor.
Add the SiSh sprite.
Set SiSh as your default initProcess in the KV store (there's a set of blocks for it at the top of the sprite's scripts).
You're done!
None! SiSh works on the base system without any additional libraries.
The first version of SiSh, an extremely lightweight shell. No arguments, no flags, no subcommands -- like you're running an EXE via Command Prompt.