cd in Terminal

Exactly what command did you run? Paste it in your reply.

 

Then you need to start it as a background process. I don't do this often enough to tell you how exactly you do it, but that's the keywords you need to search for.

(I think it's something like stick an ampersand (&) in front of the command you want ran in the background?)

 

You could definitely run in another terminal, but:
nohup yourCommand > /dev/null 2> /dev/null < /dev/null &
Should start the command in the background discarding all output, tying stdin to null, and ignoring hangup signals.

After you run this way, you will have that terminal free to keep working, and can close the terminal without terminating the command.

-Lee

 

Or just make a new tab in the Terminal app and open another shell.