At work, my ssh session to our servers time out quite frequently. It used to bother me a lot because it meant having to login to the machines many times a day, and losing the on-screen history of what I had been doing.

Not anymore. A co-worker introduced me to screen, a terminal multiplexor. In a nutshell, it manages virtual terminals that persist even when you log out. So if a connection to a server is dropped, logging in again will re-connect you to the session you had been working in.

Screen manages many virtual terminals, so one OS window can contain many Linux sessions within it, reducing desktop clutter.

Screen is quite complex, in the emacs mold: it can do many things, and has many commands, some of which are bound to keystrokes, but many of which are not. There are esoteric escape sequences that can be used to hyper-customize the environment, and more options than I can possibly understand. If you find yourself using many console windows on Unix boxes, do yourself a favor and learn enough about screen to get it working for you.

The documentation out there tends to be a bit overwhelming as well, falling into two camps: the exhaustive reference manual that begins with the command-line switches, or the informal tutorial that starts out talking about stuff you don’t understand. Here’s a shorter getting-started guide that might be helpful.

I’m tempted to write a mini-tutorial myself, but I don’t think I could really improve on what’s out there. I will give you my .screenrc file:

# Ned's .screenrc
escape ^L^L
vbell off
defscrollback 8000
hardstatus alwayslastline
hardstatus string '%{= KW}%-w%{= gW}%50> %n %t %{= KW}%+w%< %{= kG}%-=%{-}'

What does this do?

• Sets the escape character to ^L, because I don’t need that for any real use, and the default ^A is too handy for command-line editing.
• Turns off the visible bell, which is too much flashing for me.
• Sets a scrollback buffer of 8000 lines, because I like to look back through my console window for old stuff. One thing about screen: it manages the console window such that your real console window never scrolls, so you have to change where you store your off-screen lines. Your true console window doesn’t need them anymore; “defscrollback 8000” configures screen to keep them for you.
• Sets the hard status line to be the last line in the window, and to give it a simple tabbed look. This makes the last line in the window a list of your current screen sessions, in a nice green-on-gray theme.

Screen is a god-send.