Your typing is displayed in the top half of the screen, and the other user's typing is displayed in the bottom half. The user must accept your talk request by typing the talk command using your username. If you would rather not be bothered by other users' talk requests and write messages for you, you may refuse messaging with the command mesg . Refusing commands is good only throughout your session. When you log back in, messages will be accepted again.
Usage is shown below.
The command ping host.domain checks your network connection to another machine. If you are able to connect to the remote machine, ping will respond by showing the receipt of data packets from the machine. If you are not able to connect, you will need to interrupt the program with CTRL-C since ping will continue trying to connect until it succeeds.