The following document is Depends on whether you’re trying to find documents where words contains both elements (text and here) using $all:

db.things.find({ words: { $all: ["text", "here"] }});

or Else  either of them (text or here) using $in:

db.things.find({ words: { $in: ["text", "here"] }});

Choice 1:

To begin the console and execute this:

db.version()

Choice 2:

To open a shell console and do:

$ mongod --version

To show like this one:

$ mongod --version
db version v3.0.2

You can using the following code:

collection.find({}, {"sort" : ['datefield', 'asc']} ).toArray(function(err,docs) {});

You should manually create a data folder for after installing the MongoDB.

By default MongoDB will store data in /data/db,
but it won't automatically create that directory. To create it, do:
$ sudo mkdir -p /data/db/
$ sudo chown `id -u` /data/db
You can also tell MongoDB to use a different data directory,
with the --dbpath option.

For further information go to MongoDB wiki page.

You can use your collection:

db.collection.getIndexes()

http://docs.mongodb.org/manual/administration/indexes/#information-about-indexes

You can do this one:

BasicDBObject doc = new BasicDBObject( "name", "Matt" );
collection.insert( doc );
ObjectId id = (ObjectId)doc.get( "_id" );

This is a API structure of mongoose.model:

Mongoose#model(name, [schema], [collection], [skipInit])

The following statement is What mongoose do is that, When no collection argument is passed, The Mongoose produces a collection name by pluralizing the model name. If you don’t like this behavior, either pass a collection name or set your schemas collection name option.

For the example:

var schema = new Schema({ name: String }, { collection: 'actor' });

Or Else

schema.set('collection', 'actor')

Or Else

var collectionName = 'actor'
var M = mongoose.model('Actor', schema, collectionName);

You only toll the documents with sent_at defined with a value of null (don’t count the documents with sent_at not set):

db.emails.count({sent_at: { $type: 10 }})

The version of Mongo 2.2, To add a field multiplex and set it to true

db.Collection.update({query},
{$set: {field1: "f1", field2: "f2"}},
{multi: true })

It isn’t must related to MongoDB. the language on computer B was not defined correctly. so i will fix it by typing.

sudo locale-gen en_US en_US.UTF-8
sudo locale-gen it_IT it_IT.UTF-8
sudo locale-gen xx_xx xx_XX.UTF-8 …
sudo dpkg-reconfigure locales

The command make a configure that the needed locales. After those steps mongorestore got back working as usual.