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Hello the beautiful people.

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And welcome back.

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I left you with a bit of a cliffhanger in the last video where you learned all about the basics of piping.

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Now, in this video, we're going to take what you learned about the basics in the previous video.

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And in this video, we're going to level it up and teach you some advanced piping techniques.

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So with the basic stuff you learned last in the last video about just taking the output of one command

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and piping it directly into the input, into the standard input of another, that doesn't leave much

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room for flexibility, whereas there's loads of really cool things that you can do with your pipelines

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if you learn just a few more techniques.

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So in this video, we're going to go over those advanced piping techniques and by the end, you know

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how to make advanced pipelines using the T and X args commands.

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So let's go ahead and jump into it.

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All right.

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So let's just have a quick recap of what we did in the last video.

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So in the last video, we use the data command to get loads of system information about our computers

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clock.

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And what we did was we passed that data into the cut command because we just wanted to cut out the day

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of the week, which is a monday.

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Now to cut out the day of the week, we have to say that this data is actually broken up into several

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columns and each column is separated by a space.

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Now, another way of saying that is that each column is delimited by a space as a fancy word in computer

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lingo.

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And so what we did is we gave the the cut command a delimiter, and we said the delimiter is a space.

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And now once we've said, okay, each column is split up by bi spaces, which field do we want?

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Which column do we want?

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What is the first column now?

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Fields in the command are called sorry, what columns in the command are called Fields.

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So we just said fields equals one.

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And when we press enter, that cuts out Monday.

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So that's what we did in the last video.

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Then I gave you a little bit of a challenge.

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I said, Hey, how can we go about actually saving this information into a file but at the same time

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also pass it down into the pipeline?

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So how can we save it into a file, but also pass it down into the cut command so that it can be operated

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on so we can get Monday out.

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So we're trying to do two things at once.

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So to do that, we actually need to have another command called the T command.

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So let's take a look at how the PT command works.

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So here's an image of how the T command works.

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Now I'll put a link to the original picture in the video resources, but you can see here that we have

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a pipe between two commands.

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So here's a command over on the left and we have another command over here on the right.

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And in the middle we're using the PT command.

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Now, we haven't covered what these specific commands do.

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It doesn't actually matter so much.

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What I want you to focus on is the PT command in the middle and just understand that we're trying to

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pipe two commands together now, just like a t junction in a pipe of water, we can use the PT command

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to cause our data to flow into directions.

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We can cause it to flow horizontally as well as flow vertically downwards into other files.

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You can imagine it working like that.

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So this, the PT command allows us to pass the data on to the rest of the pipe, but it also allows

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us to keep it in a file.

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So you can see here that we've got a command on the left that is trying to pipe its data across into

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another command on the right.

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In the middle, though, we pipe it through the PT command and the PT command, we give it a command

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line argument of file txt that could be any file name that you want.

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And what happens is the data does pass all the way through from the standard output of one command to

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the standard input or the other.

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But it also falls down.

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You can imagine it falling down from your command line into a file called file that txt or whatever

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file name you gave the PT command.

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So that's how the PT command works.

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In theory, this is how this graphic works.

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Let's go ahead and see it work in practice.

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Okay.

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So now that you understand how the PT command works, let's just have a quick refresher of our command

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pipeline.

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We have the date command, which gives us a whole bunch of information about our systems clock.

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And we wanted to cut out the Monday or whatever day of the week it actually is.

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So we take the date command and we piped it into the cut command.

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Now we notice that the data is broken up into columns that are separated by spaces.

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So we say, Hey, cut command, we have a delimiter.

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That's a space.

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The data is delimited by spaces and we want the first column or as the command calls it, the first

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field.

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And that gives us the day of the week, which in this case is Monday.

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Now, the challenge was we want to not only have that come out, we also want to save the entire date

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into a file called called full date txt.

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So here's how we would do that.

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I'm going to press the up arrow key to get where we got before.

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Now what I'm going to do is I'm just going to squeeze in here the t command.

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Okay?

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Now the t command is going to put one of those like T junctions in our pipeline.

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You need to imagine it in your head.

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Okay.

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So what's going to happen is the data is going to pass all the way through the pipeline horizontally.

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So it's going to pass from the date command standard output and go into the standard input of the cut

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command.

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So it's going to flow straight the way through.

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But now what the T command is going to do is it's going to allow us to save the data vertically downwards.

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So you can imagine it being like a big letter T, like a big T junction.

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The data is going to go downwards into the file called full date dot txt.

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So here we are.

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The data is going to go horizontally down.

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Oops.

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I've opened a new term for my bad that is going to go horizontally across.

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Okay.

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And it's also going to go vertically downwards into a file called full data txt.

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So when we do that, we see that the output of the day of the week has still happened because that was

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passed through the cut command of the cut command, spit it out to its standard output, which is still

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connected to our terminal.

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But when we open up our file explorer, we can see that now we have a file called Full Data.

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TXT I deleted all of the other ones we had before, so we were starting afresh and now we have full

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data.

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TXT now when I open that well hey we can actually see that all of the data data has been indeed saved

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in a file called full date dot txt.

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Isn't that awesome?

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That's proper.

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Cool.

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Right.

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So what happened was the date command spat out all of its information all the way across the pipeline.

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And when it got to the T command, the T commanders took a snapshot of the data in the pipeline and

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passed it down into a file called full date txt.

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So that file contains all of the data that's coming out of the date command.

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But then the data was passed on into the cut command which did some processing and that spat out the

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day of the week, which in this case was Monday.

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Now, I've got a quick challenge for you.

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Okay?

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And I think you can do it.

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What I want you to do is I want you to instead of having the the day of the week spit out to the terminal,

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I want you to see if you can figure out how you can use redirection to actually cause that data to be

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saved in a file called today dot txt.

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Okay.

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So instead of having the day of the week spee spat it to the shirt, spat out to the terminal.

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I want you to have it saved in a file called today.

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TXT but also you still need to have the PT command in here.

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So I want you to press the upper arrow key to get what you've got before and now do the redirection.

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So I'm going to pull the video now and then come back and see how you did.

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How did you manage it?

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Did you do it?

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Well, this is how you this is how I'd go about it, right?

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So I would just right at the end here, because here's where the data is actually coming out from.

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I would just have a redirection from standard output into a file called today dot txt.

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And it's literally just that simple.

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So once we've done that, if I go ahead and press enter, we can see that when we open up our file commander

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here.

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We've now also got a file called today dot txt and inside there it has saved the data the day of the

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week, which in this case was Monday.

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Let me delete both files to so we can see this in all of its glory.

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We've got no files.

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I'm going to press the up arrow key press enter.

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And when we take a look ha ha.

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We've actually managed to save all the data into full data.

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TXT And we've also managed to save just what we wanted using redirection into today.

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TXT isn't that awesome?

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Right.

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That's kind of that's that's really awesome.

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I think so.

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Anyway, so what we've got here is the T command basically takes a snapshot of the data that's flowing

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through the pipe at that point and saves it in a file that, that you give it and then redirection will

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also do the same.

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But once you've redirected standard output, you can no longer pass it down the pipe.

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So that's why we use the PT command.

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The T command allows standard output to continue flowing down the pipe, but also allows you to effectively

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redirect it to a file and take a snapshot so that it's saved there.

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So another way of saying that is that once you've done redirection, you can't do any more piping.

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So once you've redirected standard output like we have here in the today txt, we can no longer do any

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more piping down down the pipeline.

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It's going to maximize the terminal.

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We can once we've done this redirection to today, that's the end of our piping days.

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But what we could do if we wanted to save all the data into the txt but continue the pipeline, then

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what?

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Then that's when the t command would come in.

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So we do for example today txt in the T command and now we can continue to pipe.

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Okay.

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So just again, if you do redirection of standard output, that means no more piping.

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If you want to take a snapshot, but continue piping, that's when you use the T command.

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And now I could continue piping on down.

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Okay.

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So I wanted to also cover the x args command in this video, but I think we're pushing it for time here.

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I hope that that has made it clear what the T command is.

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In final summary here, for the T command, the T command allows you to save a snapshot of the data

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and continue doing your piping, whereas just using redirection will save a snapshot of the data.

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But you can no longer do any piping.

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So if you want to keep building your pipeline but keep a snapshot of the data, use the T command instead.

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So in the next video, what we're going to do is we're going to have a look at the x args command,

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which is a really powerful command that allows you to turn your your pipe data into command line arguments.

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Ooh.

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Okay.

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So let's go ahead and I'll see you there in the next video.