zDev:~ mac$ mongorestore -u user -p pssword -d my_db path/to/bson 
connected to: 127.0.0.1
Thu Jun 28 18:46:26 /Users/path/to/bson/groups.bson
Thu Jun 28 18:46:26 going into namespace [my_db.groups]
2 objects found

Thu Jun 28 18:46:26 /Users/path/to/bson/users.bson
Thu Jun 28 18:46:26 going into namespace [my_db.users]
1 objects found

Thu Jun 28 18:46:26 /Users/path/to/bson/system.indexes.bson
Thu Jun 28 18:46:26 going into namespace [my_db.system.indexes]
Thu Jun 28 18:46:26 { name: “_id_”, ns: “my_db.groups”, key: { _id: 1 } }
Thu Jun 28 18:46:26 { name: “_id_”, ns: “my_db.users”, key: { _id: 1 } }
2 objects found