[[!meta title="Using Screen"]] ## Why? `screen` is a handy tool. It lets you get more out of a terminal session, whether in a window, via ssh, or by some more esoteric means. Its original reason for existence was allowing you to switch between subsessions on a [video-display terminal](http://en.wikipedia.org/wiki/Video_terminal), but it grew to allow sessions that could be detached and reattached (if you went home for the day, or say you were connecting via a glitchy network) and eventually to allow the same session to be simultaneously accessed from multiple places. ## Getting Started 1. Pick a machine to run your screen session on. If you don't know of any options, athena.dialup.mit.edu (Athena Dialup) is a good choice. 2. ssh to that machine. 3. run `screen` 4. Do stuff. To detach, type "C-a d" (That's control+a, release both keys, press 'd'.) . To reattach, type `screen -dr`. If you close your ssh connection without detaching, or lose your network connection: 1. run `screen -dr` 2. Do stuff. The `-dr` means "find my screen session, detach it from wherever it's attached if it's attached, and reattach it here." Once you're comfortable with this, hit "C-a C-c". This creates what screen calls a new "window"; it should give you a new shell prompt, and you can do stuff at it. If you want to switch back to the old "window", hit "C-a C-a". You can create as many "windows" as you want; you can switch to the first 10 of them with "C-a 0" through "C-a 9" and see a list of what's open with "C-a w". ("C-a C-a" actually means "switch to the previously used window".) A useful shorthand: `screen -dR` is like `screen -dr` except it adds a "if I don't already have a session, create one" step. You can use `screen -x` to attach a screen session that's already attached somewhere without detaching it first. This can have side effects if the other place is already attached or is in a window that is a different size than your current one. It's useful when you want to share context between different screens, or even different people, but doing it when you're not sure where else your screen might be attached has privacy implications. ## For More Information `screen` can do lots of stuff. If you have a while to burn, run `man screen` at the shell prompt. It may be helpful to do this inside of `screen` so you can put it down and come back to it later.