hostname

hostname is a console variable available in all Source games. This string ConVar changes the name of your server as it would appear on the server list.

Realistically this could be used in both singleplayer and multiplayer games, but it's useless for singleplayer anyways. In addition, hostname can contain up to 64 characters, not more.

Syntax: hostname <string>

You need to add quotation marks if there is spaces in the hostname. For example: hostname "My server name".