What version of MongoDB is installed on Ubuntu

To be complete, a short introduction for "shell noobs":

First of all, start your shell - you can find it inside the common desktop environments under the name "Terminal" or "Shell" somewhere in the desktops application menu.

You can also try using the key combo CTRL+F2, followed by one of those commands (depending on the desktop envrionment you're using) and the ENTER key:

xfce4-terminal
gnome-console
terminal
rxvt
konsole

If all of the above fail, try using xterm - it'll work in most cases.

Hint for the following commands: Execute the commands without the $ - it's just a marker identifying that you're on the shell.

After that just fire up mongod with the --version flag:

$ mongod --version

It shows you then something like

$ mongod --version
db version v2.4.6
Wed Oct 16 16:17:00.241 git version: nogitversion

To update it just execute

$ sudo apt-get update

and then

$ sudo apt-get install mongodb

ANSWER: Read the instructions #dua

Ok the magic was in this line that I apparently missed when installing was:

$ sudo apt-get install mongodb-10gen=2.4.6

And the full process as described here http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/ is

$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
$ echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' | sudo tee /etc/apt/sources.list.d/mongodb.list
$ sudo apt-get update
$ sudo apt-get install mongodb-10gen
$ sudo apt-get install mongodb-10gen=2.2.3
$ echo "mongodb-10gen hold" | sudo dpkg --set-selections
$ sudo service mongodb start

$ mongod --version
db version v2.4.6
Wed Oct 16 12:21:39.938 git version: b9925db5eac369d77a3a5f5d98a145eaaacd9673

IMPORTANT: Make sure you change 2.4.6 to the latest version (or whatever you want to install). Find the latest version number here http://www.mongodb.org/downloads

inside shell:

$ mongod --version

When you entered in mongo shell using "mongo" command , that time only you will notice

MongoDB shell version v3.4.0-rc2
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.0-rc2

also you can try command,in mongo shell , db.version()