From EUO Manual

These are some of the most relevant client.cfg options available to you. Client.cfg can be found in your EUO directory. It's unlikely you will ever have to change any of these. If you simply want to switch servers for example, it would be a better idea to download the EUO Launcher/Configurator utility.

server=euo.swut.net

Specifies which server to connect to

port=26667

Specifies the port to connect to

no_share=1

Having no_share set to 1 will disable square-sharing with party members - ie they will block your movement

old_lighting=1

Forces the client to not use shading - a faster and more compatible (and uglier) lighting system (see the FAQ for more info)

dir_msg=1

Display movement messages

hide_bar=1

Hide the health bar above your head

old_style_skills=1

Use the old skills list formatting where all available skills are displayed in related groups.

rage_bar=1

Displays rage bar above your head

no_fps_limit=1

Disables inbuilt fps limiter. EUO will run at nearly 100% cpu and the fps will be as high as your computer can handle