well u should download the hlds (halflife linux dedicated server) i'm pritty sure the latest version is hlds 4.1.1.0. file name "hlds_l_3110_full.bin". once installed u must download the esflinux zip "esfb100.tar.gz" can be downloaded here
http://scmgames.scm.tees.ac.uk/website/patches.html just unzip this file into the hlds dir i'm pritty sure the uzip command is tar -xzvf "esfb100.tar.gz" then just create a quck script to load the server so u dont always have to input the same commands. . .
oh if the linux server is sharing internet connection with ur computer and u want to play in the server u will have to change the port "+port *****"