A simple command
First let's run a simplest shell command:
echo "Hello Docker!"
Now we run the same command again, but with Docker:
docker run alpine:latest echo "Hello Docker!"
Doesn't look different in anyway, does it? That's how a container is supposed to be, just to wrap and isolate a process, without changing how the process behaves.
But what's the point of all this if running inside a container doesn't make any difference?
In the following steps we're going to run something different, to see a bit more.