Hi, I love the concept and think it's really cool! How did you do the console printing with the Cat command. Did you intercept it, print the "meow", then call Cat on the file?
The entire app is actually an SSH server implemented entirely within Go. The different commands are all manually simulated in Go, there is no shelling out possible because of security concerns.
The code is all open source at https://github.com/hackclub/jobs. It's the same concept I used for https://github.com/zachlatta/sshtron.