I am currently working with msfvenom on OS X. But I wanted to know, the terminal commands to open a specific port say for example 4444. Can someone please help me out with this?
You can use the terminal command
nc -l 4444 to create a server that listens on port 4444. However, I think your question really is about opening a port on your router. If someone else out on the internet somewhere is trying to connect to you on port 4444, the router you have acts as a boundary between you and them, and most often all incoming ports by default are closed. So even if you run a server on your Mac and it's listening on port 4444, traffic on that port needs to be allowed through at the router level.
Please give us more info so we can help you.
You can use python to run a simple server that opens whatever port you wish.
python -m SimpleHTTPServer 4444
If you have no firewall, the port is now open. Press Control + C to quit the process and close the port again or test the port from your client as needed.
If you have the default firewall, you will be prompted to actually open the port:
Lastly, if another process has the port open, you'll get an error of the stack trace that ends with the socket error indicating the port is already in use:
socket.error: [Errno 48] Address already in use
That's it - ports open on OS X quite easily unless you've made a custom firewall setting.