Included in the server installation and set up files is a read me file, this contains all the commands that administrators (ops) can use, however quite often ops do not have access to this file. The commands are as follows:
/op This turns a player into an administrator (op) they can use all OP commands.
/deop Removes administrator (op) permissions from a user.
/kick Kicks a player from the server, they can rejoin instantly.
/ban Bans a player from the server, they can not log back into the server with the same account.
/unban Removes a players ban, they can rejoin once unbanned.
/banip This IP bans a player, they cannot rejoin with the same account or a new account. IP bans can only be removed with direct access to ban-ips.txt by the main administrator.
/say Sends a chat message without the name.
/setspawn This sets the current location of the player executing as the new spawn location for all players joining the server after it has been set.