GNU screen is described as the console multiplexer. This really means that if you are a console person like me, instead of needing multiple ttys open or multiple xterms (etc.) open, you can have just one open and run multiple instances of bash within one console. Screen also has the nice side effect that you can start multiple sessions and disconnect from the screen session while leaving your applications running and then come back later and reconnect to the session. This is very nice for running jobs on remote machines involving applications which need a terminal to attach to.

To start we install screen (on Debian)

apt-get install screen

Next we start screen with

screen

we should then get our bash prompt back. All screen commands start with the keystroke CTRL-a. We'll learn the most important one first CTRL-a ? This shows us the keystroke reference for screen. Now we'll list the open windows with CTRL-a w. We see that we only have one window open. Let's fix that by creating a new window with CTRL-a c. Now CTRL-a w shows us windows 0 and 1. To switch back to the first window, we use CTRL-a 0.

There are many nice features to GNU screen that we won't cover, so I suggest as always, read the man page and learn the ones that help you out the most. If anyone starts using screen and finds cool features, please feel free to bring them up in a future PCLug.