The first thing we’ll need is the screen package.

sudo apt-get install screen

Now let’s create a user for steam and switch to it.

sudo adduser --disabled-login steam
sudo su - steam

Let’s download gSteam, my frontend, and set it executable for only steam.

wget http://www.dirty-motherfucker.org/steam/gSteam.sh
chmod 700 gSteam.sh

Now we can install the steam client.

./gSteam.sh install steam

As noted in my post regarding the L4D server, if the installation does not seem to properly start or
hang, you can try to create a Steam.cfg file (in the homedir) with preferred content server ids.

http://www.dirty-motherfucker.org/blog/2008/12/26/running-a-source-dedicated-server-for-left-4-dead/

After you get the magic line “Steam Linux Client updated, please retry the command” you are ready to
install some games. So let’s install Team Fortress 2.

./gSteam.sh install tf

The identifiers for the games can be obtained with:

./steam -command list 

The “No installation record found at…” messages can be safely ignored.
Now you will have to wait until the game is fully downloaded. This can take from “forever” to
“until the fucking end of time” in some cases. The old Steam.cfg can help here as well, but
I personally found that patience is the best tool.

Once the installation is completed a profile template for tf will be created. gSteam will try its
best to determine some default parameters. You should edit it nevertheless to at least adjust
the name of your server (and possibly the profile).

If everything worked fine you can now simply

./gSteam start tf2

and the thing should be running.

Installing other games is as simple as:

./gSteam install l4d_full

Let me just add that the script is far from fail-proof. Especially error-cases aren’t properly handled. But it saved me a lot of time so I thought I’d share it.
Hope it helps someone else ;)