Commands of the server

I need to know all the commands(/gen, etc...) about the
server i can use to create a map, or to modify who can build on mine or not.

i dont know how to do to delete what a griefer done.
(like a undo player).

the /commands is really incomplete for me.
If someone can send me by provate message
the list of the commands. thx.

u can do /help gen
and u can do
/undoplayer [playername] duration
for duration i do 600w usually
for all commands of world do /commands world