I'm not able to execute any unix commands on my Mac OS Terminal. I was adding a path to my Scala Installation Location.

I'm not able to execute any unix commands on my Mac OS Terminal. I was adding a path to my Scala Installation Location.

You've broken your $PATH environment variable, by the looks of it in ~/.bash_profile.
To fix:
Start Terminal.app (with error message as you posted).
Manually set $PATH:
export PATH=/usr/bin:/bin
Edit your ~/.bash_profile:
vi ~/.bash_profile
Remove the ?? characters from the scala path. That looks like it might be an invisible character, so I would recommend deleting the line and retyping it.
Save and test.