 Okay, picking up right where we left off last time, last time we were just doing basic substitution inside our file here called text, again with just some random lines I threw in there just to give me something to work with. This time we're going to look at not just replacing strings, but giving it a little bit of a somewhat simple, very simple, regular expressions to indicate the beginning and the end of a line. So again, we're going to use set, and again, this is part of a series. There should be a playlist on the screen I suggest watching from the beginning of the playlist. But if you feel like you can jump in here, jump in here. This is just the second tutorial you didn't miss much in the first, if you ever used set before you probably already know what it does. But we're going to do some substitution. Now if you remember from last time, the s here means that we're substituting, and the g means globally means we're going to replace everything, not just the first instance of each line within the text file. And what are we going to replace? In this case, let's say just the letter t. That's what we were working with last time, because there's lots of t's in here. And we'll replace every t in the file with o, o, o, o. So when we hit enter, we get instead of tiny, we get o, o, o, e, me. And then we got o's there for the t in toes, and o in this instead of the t. So basically every t is replaced with four o's. So let's say I just wanted to replace the t that starts at the beginning of each line. So that would be this and tree are both the beginning of the line. So we're looking for a t at the beginning of the line. What we can do here is we can give it the carrot symbol, which on a standard keyboard, most, I know different people have different keyboards, but it's over the six on most keyboards. And so now it's saying this carrot indicates the beginning of line. So it's saying we're looking for the beginning of line t. So it's still kind of like it's part of the string, you know. And what we're going to do is we're going to replace it with o, o, o. So now I'll hit enter. And once again, we don't have our dash i in here. So we're not modifying the original file. We're just displaying it differently. We're going to hit enter here. And you can see that not all of our t's have been replaced, but only the t's that are at the beginning of each line. And of course, I can take that one step further. Maybe I just want any th's at the beginning of the line. So here we have three and this at the beginning of the line. I can change it to say beginning of the line th. Any th at the beginning of the line replace it with o, o, o, o. And there we go. We've only got one change. And it's that one line that begins with th. We can do the same thing with the end of a line. Now the carrot symbol indicates the beginning of line. Well, a dollar sign indicates the end of a line. So this is going to find every line that ends with a t. It's because it's going to be t and then the end of the line. And we are going to replace that with o, o, o, o. And I'll hit enter. And you can see we get the t right there, o, o, o. And we can do it with ease as well. In this case, we'll, or any string, but we have three that ends in e and twice that ends in e and they're both at the end of the line. We'd enter and you can see we've got o, o, o there. And of course, if we did two ease, it would only affect the three because there's only one e and twice and then the end of the line. And again, I cleared the screen by hitting ctrl l there. You can also type clear. So again, we'll quickly review because that was kind of short. Again, said. And then inside single quotes here, s for substitute. I always put in my three slashes there, otherwise I get confused. And then g, once again meaning globally, we're just going to substitute all instances of this, not just the first on each line. And we're going to say either a line begins with t and replace it with capital t inside our text file. Again, we don't have the dash i in here. So we're not actually modifying the file yet. And there we replaced both these t's with capital t's. And then we can do the same thing, only say that and then dollar sign for end of the line. And we capitalized the last, if the last letter was a t with a capital t. So again, still basic, but moving forward a little bit. I hope you're finding these tutorials useful. Got plenty of said tutorials coming up for you in the coming weeks. Please visit filmsbychrist.com, that's Chris at the K. There should be an annotation on the screen for the entire playlist. Also in the description should be a link to my website again, filmsbychrist.com, Chris at the K. And there, on my YouTube channel and there, you can search through my videos. And I got plenty out there on shell scripts and other programming languages every Monday, some sort of shell tutorial for the Linux operating system. But again, said is a used on many operating systems, Unix like and Unix based. And said is also available for Windows. It's just not installed by default. So said is very useful tool. We're going to get to know it a little bit better in the coming weeks. Hope to see you next week. And I hope you check out the playlist. And I hope that you have a great day.