db.users.insert({name: 'paulo'})
db.users.insert({name: 'patric'})
db.users.insert({name: 'pedro'})
db.users.find({name: /a/}) //like '%a%'
out: paulo, patric
db.users.find({name: /^pa/}) //like 'pa%'
out: paulo, patric
db.users.find({name: /ro$/}) //like '%ro'
out: pedro
