kodie@ubuntu:~$ minetestserver
Automatically selecting world at [/home/kodie/.minetest/worlds/DarkNess]
4: Bind failed: Address already in use
23:38:38: ACTION[main]:         .__               __                   __
23:38:38: ACTION[main]:   _____ |__| ____   _____/  |_  ____   _______/  |_
23:38:38: ACTION[main]:  /     \|  |/    \_/ __ \   __\/ __ \ /  ___/\   __\
23:38:38: ACTION[main]: |  Y Y  \  |   |  \  ___/|  | \  ___/ \___ \  |  |
23:38:38: ACTION[main]: |__|_|  /__|___|  /\___  >__|  \___  >____  > |__|
23:38:38: ACTION[main]:       \/        \/     \/          \/     \/
23:38:38: ACTION[main]: World at [/home/kodie/.minetest/worlds/DarkNess]
23:38:38: ACTION[main]: Server for gameid="minetest" listening on port 30000.
creative inventory size: 176
23:38:38: ERROR[main]: ERROR: An unhandled exception occurred: ServerError: Failed to bind socket (port already in use?)

In thread 7f4a72dc7740:
/build/buildd/minetestc55-0.4.7/src/main.cpp:2179: int main(int, char**): Assertion '0' failed.
Debug stacks:
DEBUG STACK FOR THREAD 7f4a72dc7740:
#0  int main(int, char**)
(Leftover data: #1  Dedicated server branch)
(Leftover data: #2  virtual void ServerMap::save(ModifiedState))
(Leftover data: #3  void ServerMap::saveMapMeta())
Aborted (core dumped)
kodie@ubuntu:~$