I've managed to get the L4D2 dedicated server running on Linux (vanilla Debian 6), it works, but there's one major fault.
The server won't read any configuration files. It always ends up with
Setting breakpad minidump AppID = 550
Looking up breakpad interfaces from steamclient
Calling BreakpadMiniDumpSystemInit
exec: couldn't exec server.cfg
Connection to Steam servers successful.
VAC secure mode is activated.
and no setting applied. (server.cfg is in cfg directory, I've tried the +exec flag)
I would be very grateful for any advice.