MongoDB

@databases

Queries

// Show current operations
db.currentOp()
// Show long running queries 
db.currentOp()['inprog'].filter(function(x) {return x.secs_running > 10})
// Kill a query
db.killOp(12345)

Administration

// Drop database
db.dropDatabase();

Rotate logs

::

kill -SIGUSR1 <mongod pid>

Documentation