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In this section we're going to take another look at a very commonly used command.

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It's the command that we're going to look at is Docker.

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P.S. This command will list all the different running containers that are currently on your machine.

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Let's try running it right now and just see what happens.

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I'll flip on over to my terminal and I'll run Docker.

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P.S. When I run this command you're going to see some headers for a table.

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At present we have no containers running our machine.

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So we have no entries inside this table at this point.

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We've only been running images or creating containers that run very quickly and then immediately closed

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down.

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So for example when we were running Docker run a Busy Box and echo Hi there.

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That container starts up and then almost immediately exits us back to the command line.

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So if we want doctored piece to be meaningful at all we have to have some container that is running

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for some longer amount of time in order to get a container running a little bit longer.

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We could substitute the command that is executed when that container starts up.

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So rather than running echo HI THERE I'LL TRY IT Docker run Busy Box and then I'll do ping Google dot

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com.

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This is a command that's going to attempt to ping Google's servers and measured the amount of latency.

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It's a command that's going to continue running for a quite a long time.

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So here it is running right here.

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And as you can see it takes about two or three milliseconds for me to ping Google and get a response

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back.

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This command is going to continue running so we can now run a darker P.S. In a second window and we

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should see this container up here in the listing.

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I'm going to open up a second terminal window and then I'll execute Docker.

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Yes.

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And when I do so I'll then see that running container.

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I'm going to get this on one line really quickly.

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There we go.

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So this is a print up for the container that is currently running.

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That was issued the command of Ping Google dot com.

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We also see the containers I.D. which we can use for a lot of other operations it will look in to later

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on we'll see the image that was used for the container.

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We can see how long ago it was created.

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We get a status currently it's been up for 24 seconds.

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We'll see a listing of any ports that have been opened for outside access.

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And we're going to talk a lot about ports later on inside this course and at the very end.

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We'll also see a randomly generated name to identify this container in my case the randomly generated

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name was epic.

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Corey if I now flip back over to that running ping process I can press control see on my keyboard to

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stop it so press control see right now and I get kicked back to my command line as you might expect.

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If I then run Docker P.S. the second time I would not see that container anymore.

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So Dr. P.S. specifically shows running containers we can modify the docker P.S. command just a little

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bit to show all containers that have ever been created on our machine to do so we can execute Docker.

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P.S. dash dash all just two dashes.

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There we go when we execute that command we'll see a listing of all the containers that we have ever

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created.

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That's going to zoom out again.

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Again here really quickly just so I can see this table.

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There we go.

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So for every one of these containers these have all been containers that we have started up and then

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have either been shut down on our behalf or shut down naturally.

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So for each one of them we'll see the container I.D. image command when it was created its current status.

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In this case they're all exited any ports that have been opened up again we'll talk about those later

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and the randomly generated name for each one so in practice.

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We're going to end up using the docker P.S. command quite a bit to see what containers are currently

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running on our machine.

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One of the most common uses of Docker P.S. is not only to see what's running but also to get the idea

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of a running container because like I said we very frequently want to issue commands on a very specific

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container.

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And for that we need its I.D..

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All right.

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So that's a talker yes command.

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Let's take a quick pause right here and continue in the next section.