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In the last section we ran the docker P.S. command and we saw one variation of it which was Docker.

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P.S. dash dash all when we ran dash dash all on here.

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We saw that we got a print up of all the containers we'd ever started up on our machine which was kind

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of interesting because it kind of begs the question When does a container like really get shut down.

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Why does it get shut down and what happens when it gets shut down.

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So starting this section I want to start to show you a little bit around the lifecycle of a container

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which is gonna give you a better idea of what's going on behind the scenes.

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Now before first investigating or just jumping to the end like figuring out what happens when a container

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gets shut down I want to kind of go all the way to the start and really figure out what happens when

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a container is first created.

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Now we've learned at this point that to start up a new container from an image we use the docker run

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command.

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But when we looked at this diagram remember we looked at this diagram like two or three sections ago.

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You'll notice that I put some very particular terminology here I said creating and running a container

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creating a container and actually starting it up are actually two separate processes.

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So there's actually two additional commands in addition to Docker run that we can use to start up a

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new container Docker run.

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Running that at your command line is identical to running two other commands together first Docker create

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and then Docker start as you might guess the docker create commands is used to create a container out

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of an image and then start is used to actually start an image.

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But at this point you might be a little bit curious of Hey what's the distinction between creating a

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container and actually starting a container.

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Let's look at a diagram that's gonna help you understand the differences between the two.

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So we've looked at a diagram like this several times before remember on our image over here we've got

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that kind of file system snapshot of sorts.

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And we've also got a start up command the process of creating a container is where we kind of take the

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file system in here and kind of prep it for use in this new Container.

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When we create the container we're just talking about kind of prepping or setting up this file system

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snapshot to be used to create the container to actually start the container.

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That's when we actually execute the start up command that might start up the process of like hello world

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or in the case of that busy box one that we use the echo Hi there or whatever process is supposed to

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be executed inside the container.

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So again creating container is about the file system starting it is about actually executing the start

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up command.

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So with that in mind let's try flipping over to our command line really quickly and we're gonna start

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to investigate the differences between creating container and starting and container over it my my command

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line.

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I'm going to first try running the docker create and start commands with the hello world image.

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So I will first do Docker creates Hello dash world when I run that command I get this long string of

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characters printed out.

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This is the I.D. of the container that was just created I can now actually execute the hello world command

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inside of this container by running Docker start and I'm going to add on a little argument here I'm

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going to say dash a we'll talk about what that isn't just a second and then I'm going to paste the I.D.

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that was just emitted right here I'm going to paste in that really long series of characters and then

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when I run this command we'll see that familiar welcome message appear.

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So what happened here.

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Well again first off we kind of prop the container by getting that file system ready.

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Then after that we actually executed the primary start up command in there with Docker start.

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Now what was with the dash right there.

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Well to show you what's going on with that let's try running Docker start again but without the dash

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a so I going to run at Docker start and then I'm going to again paste in whoops I lost the thing I've

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got to do the create again very quickly so there's my I.D. and I'll do Docker start but without the

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dash this time.

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So when I run Docker start you'll notice that I just see the I.D. The Dash a command is what's going

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to make Docker actually watch for output from the container and print it out to your terminal.

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So the dash 8 specifically means hey kind of attached to the container so to speak and watch for output

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coming from it and print it out at my terminal.

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So when I put on Docker start dash that means give me any output that is coming from that thing.

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And when I run that boom there it is.

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So you'll notice that's a very small difference between Docker run and docker start by default Docker

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run is going to show you all the logs or all the information coming out of the container by default

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Docker start is the opposite Docker start is not going to show you information coming out of the terminal.

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All right so that's the differences between Docker run and docker start hand Docker create.

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Let's take a quick pause right here for you and come back the next section and we'll talk a little bit

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more about exactly what it meant when we saw with the docker P.S. all that exited status.

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So quick break and I'll see you in just a minute.