function serverCmdBLID(%client, %target)
{
messageClient(%client, '', "\c2" @ %target.name @ " BL_ID is: \c6" @ %target.bl_id);
}
When using a server command, the first argument is the person who used it. The rest are whatever you want them to be.
When transitioning between different string variables, or just strings, you must put a @.
NewChatHUD_addLine only works on client, serverCmd only works on the server.