To install Docker in Ubuntu Trusty 14.04 LTS, following commands can be used:

$ sudo apt-get update
$ sudo apt-get -y install docker.io

Alternatively, to get the latest version of Docker you can use this:

$ sudo wget -qO- https://get.docker.com/ | sh

To know the installed version, you have to run the docker version command, as follows:

$ docker version
Client version: 1.6.0
Client API version: 1.18
Go version (client): go1.4.2
Git commit (client): 4749651
...

Docker is also supported on Mac OS X, Windows, or cloud platforms. Docker installation guide for these platforms is available at https://docs.docker.com/.

To verify the installation, you can execute the docker run hello-world command. This command downloads a test image and runs the command in a container:

$ docker run hello-world
Unable to find image 'hello-world' locally
Pulling repository hello-world
91c95931e552: Download complete 
a8219747be10: Download complete 
Hello from Docker.

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