 So, I have this new program to do a set operations, it's called sets. This is the help, this is the month page and this program allows me to do operations on sets. So, sets that's lines in text files or bytes, characters in files. So, let's give a couple of examples. I have this file here with six lines. And I have another file with another six lines, but they are not all the same. So, with sets I can, for example, take set one and make the union with file set two. And then I have here all the lines from both files and of course, no duplicates. It's a set operation. Can also make the intersection like this. Only lines four, five and six are in both sets. Can do an exclusive OR. Then we have only the lines that are not in both sets. So lines one, two, three, seven, eight, nine. And then we can also subtract like this. And here, it makes a difference what you subtract from what. So, here we subtract two from one, so we only have what remains in one. And here, the result is different. If we change the order, if we subtract one from two, we only get what remains in two and not in one. So that's the operation on lines. We can also do this on bytes, on characters. For that, I have other files. This one here with six letters, A, B, C, D, E, F. And another one with again six letters, D, E, F, J, H, I. And for example, to calculate the intersection. It's exactly the same command as for lines, except that we have to specify that we work with bytes. And now I can do set bytes, intersect, set two bytes. And then we have D, E, F, the three letters that are common in both sets. So that was for lines and for characters, for bytes. And you can also pass the arguments here, the content of files, not with files itself, but with here documents like this. So let's again do a byte operation. And you specify this with a hash. And here on my Mac, I have to escape that character. And then I can, for example, say 1, 2, 3, 4, 5, 6, 7, 8, 9, 0. And I'm going to subtract 1, 2, 3, 4, 5. Well, let's change the order 5, 4, 3, 2, 1, like this. And what remains is 6, 7, 8, 9, 0.