How do I check if Docker is installed and running?

To check if Docker is installed and running, you can follow these steps:

Check Docker Installation: Open your terminal and run the following command:
```
docker --version
```
If Docker is installed, this command will return the version of Docker installed on your system.
Check Docker Service Status: To check if the Docker service is running, execute the following command:
```
sudo systemctl status docker
```
This command will show you the status of the Docker service. Look for "active (running)" in the output to confirm that Docker is running.

If you see the version number and the service is active, then Docker is installed and running correctly.