Shells ports

Open ports

As a shell user there is a range of ports you may use to run services, this range is port 5000 to 5500. (Both tcp and udp)

Help! Someone is using my port!

Ports are shared resources, if you're not using yours for a bit, someone else may take the port you were using before.

If you have a good reason to lay claim to a specific port, please contact an admin and we'll see what can be done.

That doesn't seem fair? I was using it first.

Well, in all honesty every user has as much right to a specific port as the next.

Based on this, the only fair and maintainable system at this point is simply 'first come, first served'.

port command

There is a custom made command available from your shell to check which ports are in use.

This is the 'port' command.

Usage of the port command

port -a will show you the available ports

port -s <port> will check if that port is available to you

Examples of how to use the port command

Find out if port 5001 is in use:

 coolfire@Lydia:~$ port -s 5001
 State for port 5001: In use
 Process info:
 -
 Done.
 coolfire@Lydia:~$ 

What you can see here is that port number 5001 is in use already.

If you are using the port yourself it will show you the PID and process name that is using this port.