core.register_chatcommand("update", {
        params = "<node> [<X>,<Y>,<Z>]",
        description = "Add node <node> at (<X>, <Y>, <Z>)",
        privs = {},
        func = function(name, param)
                local node, p = string.match(param, "^([^ ]+) *(.*)$")
                p = minetest.string_to_pos(p)
                if p == nil then
                       return false, "Invalid parameters ('" .. param .. "')"
                end
                minetest.set_node(p, {name = node})
        end,
})