WEBVTT 00:00.490 --> 00:04.420 Perhaps the strangest expansion is called the Brays expansion. 00:04.420 --> 00:06.270 Actually, let me write that down here. 00:06.280 --> 00:10.510 So the in this lecture we will learn about the brace. 00:12.310 --> 00:13.270 Expansion. 00:18.440 --> 00:19.130 So. 00:20.370 --> 00:26.730 A we it with the brakes expansion, you can create a multiple text strings from a pattern containing 00:26.730 --> 00:27.210 braces. 00:27.210 --> 00:32.460 So for example this here let me change this to here. 00:32.460 --> 00:34.740 So echo for example. 00:35.790 --> 00:38.850 And make it Oxley. 00:40.340 --> 00:47.600 And A, B, C, D and academy. 00:48.290 --> 00:50.810 And as you can see here, we can here. 00:50.810 --> 00:51.890 This is the following output. 00:51.930 --> 00:52.970 Occella Academy. 00:52.970 --> 00:53.300 Occella. 00:53.330 --> 00:54.590 B Occella. 00:54.620 --> 00:55.310 C Academy. 00:55.310 --> 00:55.700 Occella. 00:55.700 --> 00:56.600 D Academy. 00:56.690 --> 01:03.590 So patterns to be expanded may contain a leading portion called the preamble and a trailing portion 01:03.590 --> 01:06.050 called a postscript. 01:06.050 --> 01:12.230 So the brace expansion itself may contain either a comma separated list of strings or a range of integers 01:12.230 --> 01:13.430 or a single character. 01:13.430 --> 01:16.310 So the pattern may not contain unquoted whitespace. 01:16.310 --> 01:19.460 So here is an example for example. 01:19.490 --> 01:20.300 Echo. 01:20.480 --> 01:21.800 So now. 01:22.770 --> 01:23.250 We will. 01:24.550 --> 01:25.330 Right. 01:25.360 --> 01:27.680 Following example lectures. 01:27.700 --> 01:30.040 Lecture number. 01:30.040 --> 01:32.050 And here for example. 01:32.050 --> 01:35.200 Lecture number from one to. 01:36.600 --> 01:37.880 20 here. 01:38.370 --> 01:39.060 Not like this. 01:39.060 --> 01:39.540 Here. 01:39.570 --> 01:40.350 That's it. 01:40.350 --> 01:43.620 And as you can see here, lecture number one. 01:43.620 --> 01:47.700 Lecture number two, lecture number three, four, five, six, seven, eight. 01:47.700 --> 01:53.010 And from two, from 1 to 20, I think you are getting the. 01:54.200 --> 01:56.410 Logic of this expansion here. 01:56.650 --> 02:00.110 So now we can also do it like that. 02:00.130 --> 02:01.360 So clear. 02:01.390 --> 02:02.290 Clear. 02:02.290 --> 02:08.650 And echo zero one from zero 1 to 99 here. 02:08.650 --> 02:13.110 And we will get this following output here. 02:13.120 --> 02:21.880 And you can also do it from, for example, 0010012099. 02:21.880 --> 02:23.860 And you will also get this output. 02:23.860 --> 02:26.560 So if you try that sometime, something like that. 02:26.950 --> 02:35.890 And here you will also get the same output because it starts with 001 and then ends to 99. 02:35.890 --> 02:38.650 Here you can also do something like that, for example. 02:38.680 --> 02:39.460 Echo. 02:40.000 --> 02:40.660 Echo. 02:40.960 --> 02:45.400 You can use the range of letters in a reverse order like this. 02:45.400 --> 02:52.650 So from Z to A and here and as you can see here, we got from Z to X. 02:52.660 --> 02:58.040 And lastly A here for so we reversed the letters here. 02:58.040 --> 03:02.930 So and you can also reverse this numbers here. 03:02.930 --> 03:06.790 So you can also write from 99 to 1. 03:06.800 --> 03:11.930 So for example, echo 99 to 1. 03:12.080 --> 03:16.940 And here you can also do it from zero 99. 03:18.820 --> 03:27.490 Zero nine 9 to 1, and you can also do zero 99 to 0 100. 03:27.670 --> 03:33.070 And as you can see here, zero 99 and lastly, zero 100. 03:33.070 --> 03:35.700 So let's think of like that. 03:35.710 --> 03:38.470 What is this good for? 03:38.500 --> 03:43.840 The most common application is to make lists of files or directories to be created. 03:43.840 --> 03:50.560 For example, if we were photographers and had a large collection of images that we wanted to organize 03:50.560 --> 03:58.540 into years and months, the first thing we might do is create a series of directories named for example, 03:58.930 --> 04:03.330 and actually let me write it down here so you will understand better. 04:03.340 --> 04:12.100 So the first thing we're going to do is create a series of directories named, for example, year. 04:12.840 --> 04:15.290 Year and after month. 04:17.980 --> 04:18.640 So. 04:18.940 --> 04:26.140 So this way the directory names would sort in a chronological order and we will type out a complete 04:26.140 --> 04:26.920 list of directories. 04:26.920 --> 04:29.080 But that's a lot of work in this case. 04:29.080 --> 04:31.060 But in and it's error prone. 04:31.060 --> 04:35.230 So instead we could do here in next example. 04:35.230 --> 04:41.260 But firstly what we want to do here for example October, October. 04:45.250 --> 04:49.060 And the month is going to be, for example, no year year for. 04:49.060 --> 04:51.370 So first we're going to write a year here. 04:51.370 --> 04:56.650 So year is going to be, for example, 2020 4th October. 04:56.650 --> 04:59.800 And inside this we're going to have the photographs. 05:00.070 --> 05:03.910 So this is going to be directory here and this is going to be our directory. 05:03.910 --> 05:08.440 And inside this we're going to save and order photographs in it. 05:08.440 --> 05:10.870 So let's get started with our example now. 05:12.000 --> 05:13.200 And here. 05:13.260 --> 05:15.090 But first we're going to here. 05:15.090 --> 05:18.540 So firstly, we're going to go to documents or another directory. 05:18.540 --> 05:27.870 So we will want won't see the other users directories here or let's actually go to CD, my dear one. 05:27.870 --> 05:30.450 And so we don't have any files in it. 05:30.450 --> 05:31.050 That's good. 05:31.050 --> 05:35.220 And for example make their photos yet. 05:35.310 --> 05:36.360 Yeah, photos. 05:36.390 --> 05:38.640 And here we created the deer photos. 05:38.640 --> 05:40.770 So we're going to see the two photos here. 05:41.530 --> 05:42.250 Photos. 05:43.570 --> 05:44.890 And now. 05:46.550 --> 05:49.700 We will make the deal here. 05:49.700 --> 06:02.810 So now that's here, for example, my card here and from 2024 or 2022. 06:04.500 --> 06:06.210 From 2020 to. 06:07.510 --> 06:12.970 2025 and here and we will also write the month number. 06:12.970 --> 06:15.640 So in this case, the month numbers is going to be 06:15.670 --> 06:24.760 010203040506. 06:24.790 --> 06:25.660 Also 06:25.960 --> 06:31.360 070809. 06:31.840 --> 06:33.220 Uh, not zero here. 06:33.220 --> 06:36.400 Ten and 11 and 12. 06:36.400 --> 06:40.510 So the months order is going to be like this here. 06:40.510 --> 06:45.280 So let's here in order to do that, we will write it. 06:45.280 --> 06:47.200 012. 06:47.960 --> 06:48.620 12. 06:48.920 --> 06:56.280 And here let's create enter and here, let's see the magic here, LZ. 06:56.330 --> 06:58.790 And as you can see here, LZ here. 06:58.790 --> 07:04.460 And as you can see here, actually, we did an mistake here because we did write it like that. 07:04.460 --> 07:09.980 So now let's actually see what did create, uh, we what did we create? 07:09.980 --> 07:14.420 And here, as you can see here, we created actually we did mistyped the error. 07:14.420 --> 07:22.370 Instead of writing this, we need have to write two space characters so clear, let's write it again 07:22.370 --> 07:24.140 so we don't have any files. 07:24.170 --> 07:25.820 LZ And here. 07:27.090 --> 07:33.420 We will do m-code here and from 2020. 07:34.950 --> 07:36.660 To 2025. 07:36.660 --> 07:38.070 And here. 07:40.100 --> 07:42.740 Zero one from zero one. 07:44.660 --> 07:45.920 To 12. 07:47.090 --> 07:53.210 And here, as you can see here, we did create our folders for it. 07:53.210 --> 07:59.870 So, for example, this is 2021, 2022, 2023, 2024. 07:59.870 --> 08:07.190 And it goes like this to from 2021 to our 20 2512 here. 08:07.490 --> 08:11.240 And this is pretty like magic, right? 08:11.690 --> 08:14.930 So in next lecture you will also learn about the parameter expansion. 08:14.930 --> 08:16.250 So I'm waiting you in next lecture.