Done

Added persistent env that can be used to store values between commands.

Commands

• ls: created, a command to see the files in your current directory
• cat: created, a command to look at the contents of a file
• cd: created, a command to change your directory
• theme: created, a command to change your theme to one of the valid themes
• help: improved, added new commands to help

TODO

• Add more themes
• Create mobile friendly interaction
• Create accessible interaction