Can I just kill mongod to stop mongo?

It finally succeeded (Ubuntu 15.04) with

//1.find process by name:

$ pgrep mongo

1350

//2.kill mongod-process

$ kill 1350

This is quite late, but I had same problem now, and I found one easy way :

Esan-iMac:~$mongo admin --eval "db.shutdownServer()"

MongoDB shell version: 2.6.4
connecting to: admin
2015-02-19T10:54:22.574+0200 DBClientCursor::init call() failed
server should be down...

It's giving some odd messages, but it works.

And I made alias-command for running it easy.

alias stop-mongo='/opt/mongo/release/bin/mongo admin --eval "db.shutdownServer()"'

This works at least if you start your mongo manually (e.g. with --fork option).