Group Operators
$last | return the last value in a group
$first | return the first value in a group
$min | return the lowest value in a group
$avg | return an average of all values in a group
$addToSet | return a unique array of values for group
$max | return the highest value in a group
$push | return an array of values for a grouped field
$and | returns true when all values in array are true
$or | returns true when any value in its array are true
$not | returns boolean value that is opposite of input
$eq | return true if two values are equal
Comparison Operators
$cmp | return the result of a compare as an integer

help | get help for the context you are in
db | show the selected database
show dbs | show databases on server
show collections | show collections in the current db
use foo | select and use the database fooCollection commands (db.collection.)
mapReduce() | performs mapreduce
data aggregate
copyTo() | copy a collection to a new collection name
renameCollection() | rename a collection
drop() | remove the collection from the database
help() | show a list of help commands for a collection
command line options:host
hostname | hostname to connect toport
27017 | connect to port
27017 (default)u
foo | username foop
bar | password barauthenticationDatabase
arg | database
to authenticate to
mongotop | profile the resources mongo is consuming
mongostat | profile the amount of time spent in collections
mongoimport | import data from a file to mongodb
mongodump | dump contents of a database to files
mongorestore | restore contents of a dump to a database
exit | exit the shell
show users | show the users in the current db
getLastError() | get status of last error
stats() | get stats on the current db selected
help() | show a list of help commands for a dbIndexing
ensureIndex() | creates an index if it does not currently exist
reIndex() | rebuilds all existing indexes on a collection
getIndexes() | gets details on the indexes on a collection
dropIndex() | removes a specified index on a collection
compact | defragments a collection and rebuilds the indexesCursors (db.collection.find.)
limit() | constrain the size of a cursors result set
skip() | skip through some documents and then return results
sort() | return results ordered according to a sort specification
next() | return the next document in a cursor
count() | return a count of the documents in a cursor
toArray() | return an array of all documents for the cursor
explain() | get the query execution plan for a cursor
hint() | force db to use a specific index for a query
count() | get number of documents in the collection
stats() | get stats about the collection
hasNext() | true if cursor has documents and can be iterated
it | iterate on a cursorReplication (rs.)
add() | adds a member to a replica set
initiate() | initializes a new replica set
addArb() | adds an arbiter to a replica set
conf() | returns the replica set config document
freeze() | prevents a member from becoming primary
help() | get basic help for replica set functionsSharding (sh.)
addShard() | add a shard to the cluster
addShardTag() | associate a shard with a tagAuthentication
db.addUser() | add a user to system.users or admin collection
db.auth() | authenticates a user to a databaseProjection Operators ( $ )
$slice | limit number of elements projected from array
$elemMatch | project only the first element match
$ | project the first element in an array that matchesAggregation Operators ( $ )