typing MONGO_URL=somedomain does no longer work. It seems the command is deprecated. Is there still a possibility to connect to a mongo database online?
You need to either install mongodb on your system and then can connect
mongo "mongodb://user:pass@server1.mlab.com:19133,server2.mlab.com:19133/database?replicaSet=server3
or use the binary from Meteor (dependent on your OS)
$HOME/.meteor/packages/meteor-tool/1.3.4_1/mt-os.osx.x86_64/dev_bundle/mongodb/bin/mongo