Using screen with Linux and Half-Life Counter-Strike
This document explains why and how to use screen to run your Half-Life Counter-Strike server under Linux.

What is screen?
Screen is an application that is part of the default distribution of many types of Linux. It allows you to create virtual terminal screens which can be detached and run in the background, then re-attached and brought to the foreground at will. In MS-Windows terms, think of it like minimizing a window. It's still there and running, you just aren't looking at it on your desktop. Screen does the same thing for terminals like Xterm, telnet or ssh.

Do I have screen?
To find out if screen is installed on your system, go to a command terminal and type in "which screen". If it comes back with something similar to "/usr/bin/screen", you're in business. If instead it comes back with something similar to "which: no screen in /usr/bin:/bin:/usr/bin...", screen is not installed. You should stop reading this now while you figure out where to get and install it from. A good place to look is http://www.rpmfind.net.

Is screen the best method?
No, but it is a good place to start before you get into something more complicated. The first method most people learn is running a process in the foreground, like:

./hlds_run -game cstrike +exec server.cfg +map de_aztec

This will run the server just fine. Just don't close that terminal window or your server goes along with it into oblivion. Then you might ask around and learn that adding a "&" will launch the server into the background, like:

./hlds_run -game cstrike +exec server.cfg +map de_aztec &

This is even better. It launches your server and runs it in the background. Now you can close the terminal window and the server still runs. Unfortunately you can't get back to your server console and can only administer your server with RCON or something like Alfred's Admin Mod.

So how do I use it?
Get into a text terminal. Then type in the following command, which will create a virtual terminal, start your Half-Life Counter-Strike server, and return to your regular terminal:

screen -A -m -d -S hlds ./hlds_run -game cstrike +exec server.cfg +map de_aztec

You may wish to customize this your command line. The Counter-Strike Command Line editor is a great tool for figuring out how your command line should look. Just add "screen -A -m -d -S hlds " in front of whatever command line you choose.

Once you have executed the command to start screen and your CS server, type in:

screen -r hlds

This tells screen that you wish to attach to the virtual terminal you already created. The next thing you should see is your CS server's console. If you want to detach from the virtual terminal, or in other words leave the CS server running in the background, hit your "Ctrl" and "a" keys simultaneously, then hit your "d" key.

What else can I do?
Go ahead and attach to your virtual terminal with the "screen -r hlds" command. Once there, hit your "Ctrl" and "a" keys simultaneously, and then hit your "ESC" key. Using the up and down arrow keys you can now scroll through your server's console, past what would normally be visible. When you are done, hit the "ESC" key again.

Doing "man screen" from your terminal prompt will give you more information about screen and how to use it.

You said screen wasn't the best way. What is?
A couple of very useful tools for Linux administrators are hlmonitor and hlds_ld. I highly recommend you check them both out and choose what fits you best. Screen is good, but these are far better.