WEBVTT 00:00.390 --> 00:00.960 Okay. 00:01.140 --> 00:05.970 Now let's dig into the next usage and explore some basic Linux command. 00:07.060 --> 00:07.990 Now from here. 00:08.190 --> 00:09.280 Open the terminal. 00:10.120 --> 00:11.050 Now, from here. 00:11.050 --> 00:14.590 If I go to the file preferences, go to the color scheme. 00:14.590 --> 00:17.500 Here, you can change it to something else as you want. 00:18.010 --> 00:20.020 Actually, I prefer green on black. 00:20.050 --> 00:24.820 Now, not to sound like hair color, to be honest, but actually it's better for my eyes. 00:24.820 --> 00:26.260 So if I click here. 00:26.260 --> 00:28.120 Yeah, you can see that now. 00:28.120 --> 00:28.870 It is better. 00:29.050 --> 00:34.840 All right, actually, let's increase the font size control, shift the plus sign. 00:35.740 --> 00:37.630 So, yeah, I think this is better. 00:37.870 --> 00:40.880 It's increased this and this it. 00:41.860 --> 00:47.830 Now the first command, it will be Alice, as it is the command used for listing the file. 00:47.830 --> 00:56.650 So as you can see less and here all the files or directories I have on the current path so as to list 00:56.650 --> 00:57.280 commands. 00:58.240 --> 00:59.820 So I'll ask the list fight. 01:00.150 --> 01:00.640 Okay. 01:00.970 --> 01:02.980 Now we have clear. 01:03.070 --> 01:06.160 So you can see that if I type enter. 01:06.160 --> 01:11.170 And as you can see now, you can see that the screen is becoming chaotic. 01:11.200 --> 01:13.950 So to clear the screen, we will put the clear command. 01:13.960 --> 01:15.260 Clear, as simple as that. 01:15.430 --> 01:15.930 Okay. 01:15.940 --> 01:18.370 So we learned less and clear. 01:18.700 --> 01:19.280 Okay. 01:19.300 --> 01:23.250 Now, what if I want to learn more about specific command? 01:23.270 --> 01:30.550 So for example, the last command, I want to read more about it, about its option, about its features, 01:30.550 --> 01:31.030 whatever. 01:31.150 --> 01:33.980 So we will use the main command. 01:34.000 --> 01:37.000 The main command is used to, for many, one. 01:37.390 --> 01:38.980 So man less. 01:41.300 --> 01:44.700 It will show us what is the LZ command will do. 01:44.720 --> 01:48.090 So let's directory contents as you can see, LZ. 01:48.110 --> 01:52.070 This is the syntax or synopsis plus option. 01:52.070 --> 01:54.980 Whatever options, then the file, whatever file. 01:55.250 --> 02:03.500 So you can see that we have a lot of descriptions dash a, all the P, C, F or T and you can read more 02:03.500 --> 02:05.600 about it as you can see from here. 02:06.550 --> 02:07.600 Now to quit from this. 02:07.600 --> 02:10.240 You can see that for help or for quit. 02:10.240 --> 02:11.310 So let's quit. 02:11.320 --> 02:11.890 All right. 02:11.890 --> 02:15.700 So men clear, as you can see. 02:15.730 --> 02:17.260 Clear the terminal screen. 02:17.440 --> 02:22.090 And it has a lot of options that T type V, X, whatever. 02:22.720 --> 02:26.020 Q to quit now, man, man. 02:26.050 --> 02:29.050 So this is to show the manual for the manual page. 02:29.140 --> 02:29.620 Okay. 02:29.650 --> 02:33.790 So this is man, this is an interface to the system reference manual. 02:34.120 --> 02:40.800 So you can see that it has dash k, dash k, capital dash FLW options, right? 02:41.200 --> 02:42.130 All right, cool. 02:42.130 --> 02:43.600 So far so good. 02:44.320 --> 02:49.600 Okay, now if I type less, you can see that I am here currently. 02:49.810 --> 02:51.940 I want to know where I am currently. 02:51.940 --> 02:59.440 So if I type b w dx which is print working directory, it will show us that I am inside the home slash 02:59.440 --> 03:00.070 kelly. 03:00.490 --> 03:09.130 Okay, so if I type man P.W. De here, you can see that it will bring the name of the current working 03:09.130 --> 03:10.000 directory. 03:10.030 --> 03:10.240 Okay. 03:10.330 --> 03:16.390 So Brent working directory or the current directory and it has a lot of options like Dash L, Dash P, 03:16.390 --> 03:16.960 whatever. 03:16.960 --> 03:18.190 You can read more about it. 03:18.700 --> 03:20.260 Now let's clear the screen again. 03:20.530 --> 03:26.980 And now if I type ls you can see that I am here inside the home. 03:26.980 --> 03:33.940 Kelly When I typed BW D OC the Kelly Home Directory, now I want to go to the desktop OC where it is 03:33.940 --> 03:34.300 here. 03:34.300 --> 03:36.250 OC how to do such a thing. 03:36.250 --> 03:39.520 I would use the CD Command Man CD again. 03:41.340 --> 03:45.720 You can see that some of the comments are not or don't have manual. 03:45.720 --> 03:51.510 So like the CD because it's a simple command so it has not so CD. 03:51.750 --> 03:53.430 Then the name of the directory. 03:53.760 --> 03:56.070 So if I type, unless I want to go to the desktop. 03:56.120 --> 03:56.660 Okay. 03:56.670 --> 03:59.490 But remember in Linux, this is a case sensitive. 03:59.730 --> 04:03.150 So CD desktop, the D must be capital. 04:03.450 --> 04:09.220 Now you can notice that if I type desktop, I can press the tab button. 04:09.240 --> 04:15.840 So if I press it, it will autocomplete the sentence or the name of the folder or directory in Linux 04:15.840 --> 04:17.520 we call the directory not folder. 04:17.550 --> 04:19.350 In Windows we call this folder. 04:19.950 --> 04:21.420 So CD desktop. 04:21.450 --> 04:22.710 Now you can see that. 04:22.740 --> 04:23.400 Yeah. 04:23.400 --> 04:25.590 From here from tilde mark. 04:25.890 --> 04:32.970 It changed to the desktop by the way, the tilde marking the tilde mark here means it is the home directory 04:32.970 --> 04:36.120 of the current user, which is in our case it is the carrier user. 04:37.410 --> 04:38.040 No worries. 04:38.040 --> 04:40.410 We will talk about this in details later on. 04:40.410 --> 04:41.700 But for now, follow me. 04:42.900 --> 04:43.200 Okay. 04:43.230 --> 04:48.010 Now, if I want to go back, I will go see the dot dot OC. 04:48.270 --> 04:51.060 Now dot dot means the parent directory. 04:51.390 --> 04:53.620 Again, we will talk about this later on. 04:53.640 --> 04:54.450 No worries. 04:55.230 --> 05:00.990 So here we will go back to the parent directory of the desktop and the parent director of the desktop 05:00.990 --> 05:04.410 is the home directory of Linux user. 05:05.280 --> 05:05.970 Okay. 05:06.000 --> 05:07.040 Now, here. 05:07.050 --> 05:09.750 What if I want to make a new directory? 05:09.750 --> 05:13.200 I will use the command and data or make directory. 05:13.200 --> 05:20.250 So man, make that and see this is to make directory and we have other options as you can see here. 05:20.640 --> 05:23.850 So make dial and let's name a list. 05:24.540 --> 05:28.050 And as you can see here it is test. 05:28.380 --> 05:29.940 So seed to test. 05:30.210 --> 05:33.330 You can see now we are inside the test directory. 05:33.330 --> 05:35.190 Okay, so far so good. 05:35.220 --> 05:39.220 Now, you may ask me, this directory is empty. 05:39.240 --> 05:42.840 How did we go to the dot or to the dot? 05:42.870 --> 05:45.630 There is other thing called that, which is the current directory. 05:45.630 --> 05:46.860 How did we go there? 05:46.860 --> 05:48.240 It is not even exist. 05:48.240 --> 05:49.890 No, actually it is exist. 05:49.890 --> 05:51.090 But it is hidden. 05:51.090 --> 05:56.790 So if I type ls dash a this will show all the directory. 05:56.790 --> 05:58.260 So how did I know that? 05:58.260 --> 06:03.120 Just open the manually, page and press don't ignore entries. 06:03.120 --> 06:10.410 Start with dot as you can see because the dot here in Linux it will be considered a hidden directory 06:10.440 --> 06:12.240 OC or hidden files. 06:12.990 --> 06:20.430 So when I type, it will not be shown, but it will show everything which is dot and dot dot the dot 06:20.430 --> 06:25.050 here one single dot, which is the current directory which is the test directory. 06:25.710 --> 06:29.300 Now you may ask me, but what is the use for this? 06:29.310 --> 06:31.470 This is has this has no meaning. 06:31.470 --> 06:31.740 No. 06:31.740 --> 06:32.970 We will talk about it later on. 06:32.970 --> 06:33.690 No worries. 06:33.780 --> 06:38.910 And the dot dot, which means the parent directory of the current directory, which is the parent directory 06:38.910 --> 06:41.460 of test, which is in our case, the tilde. 06:42.480 --> 06:48.360 And we already mentioned that this means the home directory of the current user, which is clearly user, 06:48.360 --> 06:50.400 which is the Cally home page. 06:50.400 --> 06:52.040 So said dot dot. 06:52.650 --> 06:56.700 It will go to the parent directory and you can see we returned back. 06:56.880 --> 06:57.450 All right. 06:57.750 --> 06:59.040 So far, so good. 06:59.580 --> 07:00.930 Now let's clear the screen. 07:01.200 --> 07:04.860 Now, also, there is other options like dash p. 07:05.850 --> 07:07.820 Which means create a parent directory. 07:07.830 --> 07:10.920 So, for example, I have this here, right? 07:11.370 --> 07:18.630 So what if I want to create this tool, as you can see and inside it, I want to create a list three 07:18.810 --> 07:19.470 like this. 07:19.470 --> 07:23.130 This will not work because this tool is not exist in the first place. 07:23.130 --> 07:29.670 So for that case I will put the P, which is parent and this will create this tool. 07:30.060 --> 07:36.630 As you can see if I type ls this tool with directory it will show us the content or the yeah. 07:36.630 --> 07:41.820 The content of this tool which is history, the folder we have created. 07:41.820 --> 07:45.450 Now let's talk about another command which is the wish command. 07:45.450 --> 07:50.520 This is to search through the directories that are defined in the bath environment. 07:50.760 --> 07:55.440 So if I tap echo, this is a command used to print a text. 07:55.440 --> 07:58.260 So if I type eco hi, it will print hi. 07:58.260 --> 07:59.850 As you can see in double quotation. 08:00.090 --> 08:03.150 If I type eco hi. 08:03.390 --> 08:04.650 Also it will print it. 08:04.650 --> 08:05.850 But if I type. 08:06.640 --> 08:07.390 Echo. 08:08.220 --> 08:08.690 Shift. 08:08.880 --> 08:09.540 Hi. 08:09.570 --> 08:18.450 Now you can see that the shift for the dollar sign means that this is a variable in Linux and this variable 08:18.450 --> 08:19.370 is not assigned. 08:19.380 --> 08:24.190 But we have environment variables called the best here. 08:24.360 --> 08:26.100 So if I type it, it will see. 08:26.100 --> 08:32.160 You can see that this variable contains a listing of directories that can be search when a command is 08:32.160 --> 08:34.020 issued without its bath. 08:34.170 --> 08:36.690 By the way, this is not in Linux only. 08:36.690 --> 08:39.990 This is used with Debian or Linux generally. 08:40.320 --> 08:44.550 So Debian based or IT based or whatever. 08:44.550 --> 08:46.230 Linux distribution. 08:46.980 --> 08:50.900 Well, some of them doesn't use this or have a special meaning, whatever. 08:51.300 --> 08:56.490 But I'm talking about the popular or the popular distribution anyway. 08:56.790 --> 09:01.480 So if I type ls here, you can see this is a command, by the way. 09:01.500 --> 09:08.390 By the way, this is a utility that exists on the system that should be inside here. 09:08.400 --> 09:16.650 So if I type eco path, it should be either here, use a local spin or use a local bin or user a spin 09:16.650 --> 09:17.440 or whatever. 09:17.470 --> 09:17.710 Okay. 09:17.730 --> 09:20.550 So it must be inside one of these directories. 09:20.670 --> 09:28.050 So if I type which by the way man which we learn that which locate a command as you can see, it will 09:28.050 --> 09:29.280 look at the command where it is. 09:29.280 --> 09:30.990 So which ls. 09:32.350 --> 09:39.360 As you can see SE is easiest to lose dash color or which CD. 09:39.570 --> 09:42.680 You can see that these are a built in commands. 09:43.200 --> 09:45.180 So let's look about another command. 09:45.180 --> 09:53.910 So for example, which python button is a command and you can see it is inside the user bin button here 09:54.030 --> 09:55.230 where it is located. 09:55.230 --> 09:59.330 So I'm using which command, by the way, the CD and LZ. 09:59.340 --> 10:00.630 These are a built in command. 10:00.630 --> 10:06.330 So most likely they are not existed anywhere or they are existed, actually. 10:06.330 --> 10:07.930 But we will talk about these later on. 10:07.930 --> 10:08.550 No worries. 10:08.910 --> 10:13.650 Now we have another command called Locate Man, Locate like this. 10:13.740 --> 10:16.130 This is to find files by name quickly. 10:17.070 --> 10:21.420 So as you can see in which to read the database made by update DB. 10:21.450 --> 10:24.810 So for example, locate python. 10:25.350 --> 10:29.690 You can see it will start looking for all or anything called Python. 10:29.700 --> 10:33.030 As you can see now this list to be updated. 10:33.030 --> 10:36.570 We must use this command update db. 10:37.960 --> 10:39.540 Like this, so press it. 10:39.550 --> 10:45.580 You can see permission denied for that case because after all, I'm updating the whole system or I'm 10:45.580 --> 10:48.580 updating the database from the whole system. 10:48.580 --> 10:50.840 So I must use the sudo command. 10:50.860 --> 10:51.430 No worries. 10:51.430 --> 10:57.550 We will talk about this later on the the command, by the way, if I type man sudo this is to execute 10:57.550 --> 10:58.930 a command as another user. 10:58.930 --> 11:02.770 So sudo update db. 11:04.690 --> 11:06.460 And here it will ask for a password. 11:06.670 --> 11:07.450 Of course. 11:08.360 --> 11:09.020 Which is catty. 11:09.020 --> 11:10.630 One, two, three, four, five, six. 11:10.640 --> 11:13.760 By the way, this is a stupid password. 11:14.060 --> 11:17.300 But anyway, this is just for the sake of discourse. 11:17.450 --> 11:22.010 Now we updated the database, so look it again by phone. 11:22.520 --> 11:24.530 And sorry, I mistake this. 11:24.530 --> 11:25.180 I have a mistake. 11:25.220 --> 11:28.810 Yeah, it will show us the same result. 11:29.030 --> 11:29.570 By the way. 11:30.460 --> 11:31.000 Okay. 11:31.890 --> 11:33.990 Now finally we have another command. 11:33.990 --> 11:38.040 I know we took a lot of time, but these are just the basics. 11:38.070 --> 11:38.850 No worries. 11:38.850 --> 11:45.600 We will have what we learned practically step by step, and we will repeat it over and over. 11:45.600 --> 11:48.730 So you will get used to it and you will master it in no time. 11:48.750 --> 11:49.470 Trust me. 11:49.560 --> 11:51.420 Now, finally, we have that find command. 11:51.420 --> 11:52.650 So men find. 11:53.520 --> 11:56.240 This is to search for file in directory or hierarchical. 11:56.250 --> 11:59.840 So for example, find slash. 11:59.850 --> 12:07.380 This is where we want to search the name and the name which will be by phone, for example. 12:08.500 --> 12:11.140 But you can see that it will start showing us permission denied. 12:11.140 --> 12:12.100 Permission denied. 12:12.130 --> 12:12.790 All right. 12:12.790 --> 12:15.520 So we learned that we already learned what we do. 12:15.550 --> 12:16.490 What should we do? 12:16.510 --> 12:20.050 Which is using the pseudo, as you can see. 12:20.840 --> 12:23.180 It will show us that it found some. 12:23.180 --> 12:27.150 But here we got permission denied for this for some reason. 12:27.170 --> 12:29.640 For now, we will not handle it because this is a low level. 12:29.660 --> 12:31.250 We will talk about it later on. 12:32.420 --> 12:32.740 Okay. 12:32.750 --> 12:34.820 So we found what we want. 12:34.850 --> 12:36.140 All right, cool. 12:36.170 --> 12:37.430 So far, so good. 12:37.460 --> 12:40.640 Now I will provide you with exercises. 12:41.560 --> 12:44.390 On what we have learnt here in this lecture. 12:44.410 --> 12:46.440 So you will practice with me. 12:47.380 --> 12:53.080 Now I recommend you to do the exercises because it will be very useful for you. 12:53.290 --> 12:56.710 As they say, practice makes perfect.