1 00:00:06,500 --> 00:00:08,669 You working with Linux is knowing your commands. 2 00:00:09,169 --> 00:00:12,130 So let's have a look at some essential commands to get started with. 3 00:00:14,109 --> 00:00:16,550 These are whoami, who's shown who you are. 4 00:00:17,210 --> 00:00:20,359 LS for listing information about files. 5 00:00:21,019 --> 00:00:25,990 Ipa, which is showing IP address configuration, cat, which allows you to read 6 00:00:25,990 --> 00:00:30,960 text files, and and passwd, which allows you to change your password. 7 00:00:31,660 --> 00:00:36,075 I also like Touch, which allows you to create an empty file, or 8 00:00:36,075 --> 00:00:40,490 pwd, which is printing your current working directory. Let me show you. 9 00:00:41,469 --> 00:00:45,810 To start with, I'm using who am I and who am I showing? Well, my current username. 10 00:00:46,950 --> 00:00:53,149 Have you seen that the current username is also in the prompt? So in the prompt you can see that I'm student at localhost. 11 00:00:53,810 --> 00:00:55,409 And then we see a colon tilde. 12 00:00:55,929 --> 00:00:59,509 The tilde is indicating my current working directory. 13 00:01:00,130 --> 00:01:04,719 You can request that directory using PWD for print working directory. 14 00:01:05,400 --> 00:01:11,450 And oh, by the way, the dollar at the end of the prompt is an indicator that shows that 15 00:01:11,450 --> 00:01:17,500 I'm currently logged in as a non root user, an ordinary user, also known as a non privileged user. 16 00:01:18,599 --> 00:01:22,200 Let me type LS LS is showing files in the current directory. 17 00:01:22,799 --> 00:01:29,356 If I use touch new file then the result is that I just created a new file, an 18 00:01:29,356 --> 00:01:35,913 empty new file that is meta name newfile in case you are wondering what is that good for? 19 00:01:35,913 --> 00:01:42,469 Well, this allows you to verify that you can write into a directory that's actually pretty useful. 20 00:01:43,629 --> 00:01:48,324 Let's verify that the file really is empty by using cat on new 21 00:01:48,324 --> 00:01:53,019 file. We see nothing. Yeah, that's on purpose because the file is empty. 22 00:01:53,799 --> 00:01:57,424 Can we do that on another file? Well, when I use LS A, 23 00:01:57,424 --> 00:02:01,049 then I can see files that have a name starting with a dot. 24 00:02:02,489 --> 00:02:04,790 They are effectively hidden files. 25 00:02:05,370 --> 00:02:08,939 But the Linux operating system doesn't know about hidden file properties. 26 00:02:09,439 --> 00:02:13,295 And that is why there's a convention. And the convention is that if a file has 27 00:02:13,295 --> 00:02:17,150 a name that starts with the dot, most utilities won't show the name of the file. 28 00:02:18,199 --> 00:02:23,784 So I want to show you the contents of this bashrc and this BASHRC is 29 00:02:23,784 --> 00:02:29,370 a startup file. And look at that, that's all the contents that it has. 30 00:02:29,870 --> 00:02:35,180 For now we don't care about the contents that much. It's about showing the contents of configuration files. 31 00:02:37,159 --> 00:02:43,889 Now I would also like to show you the PASSWD command. PASSWD allows you to change your password. Before 32 00:02:43,889 --> 00:02:50,620 doing so, you do need to enter your current password and then you need to enter the new password. 33 00:02:51,319 --> 00:02:51,659 Oh boy. 34 00:02:52,340 --> 00:02:55,330 It's complaining that the password is the same as the old one. 35 00:02:55,889 --> 00:03:00,099 And then we get an authentication Token manipulation error. 36 00:03:01,280 --> 00:03:06,710 Now that's not very obvious what it means, but what it means is that it has failed to set your password properly. 37 00:03:07,349 --> 00:03:09,680 And for that reason the password is unchanged. 38 00:03:10,710 --> 00:03:17,199 For now, I'm just going to leave it as is. I'm okay that the password is unchanged, unlike my previous password. 39 00:03:17,909 --> 00:03:19,610 I want one more thing, and that is ipa. 40 00:03:20,889 --> 00:03:24,180 In Linux, frequently you want to access your Linux system remotely. 41 00:03:24,680 --> 00:03:28,689 And in order to access your system remotely you need the IP address. 42 00:03:29,669 --> 00:03:32,530 IPA is showing the current IP address configuration. 43 00:03:33,590 --> 00:03:37,090 On most Linux distributions you will see at least two interfaces. 44 00:03:37,740 --> 00:03:40,449 There is the LO interface with the IP address 127.0.0.1. 45 00:03:43,300 --> 00:03:47,020 This is the loopback interface and it's used for internal communication. 46 00:03:48,740 --> 00:03:55,250 The interface that really matters is right here, the ENS160 interface. 47 00:03:55,949 --> 00:03:58,590 The name of that interface depends on your Linux kernel. 48 00:03:59,110 --> 00:04:04,939 So if you see something that is not ENS 160, that's okay, don't worry about it. That's completely normal. 49 00:04:06,020 --> 00:04:10,020 The thing that you want to know about your interface is which IP address is it using? 50 00:04:10,680 --> 00:04:16,670 Well, here highlighted we can see the IP address 192.168.29.137. 51 00:04:17,110 --> 00:04:21,959 So if I ever want to access my system remotely, this is the IP address that I need. 52 00:04:22,980 --> 00:04:27,480 Oh, and did you notice that on Linux all interfaces also have an IPv6 address? 53 00:04:28,000 --> 00:04:34,470 Don't worry about these IPv6 addresses too much. Most people don't use them, but they need to be here. 54 00:04:35,089 --> 00:04:38,709 And if ever you need to know about it, IPA 55 00:04:38,709 --> 00:04:42,329 is not only showing IPv4 but also IPv6 addresses. 56 00:04:43,170 --> 00:04:48,034 For now, that is enough about commands. You now have knowledge of a couple of 57 00:04:48,034 --> 00:04:52,899 commands and that makes it more useful to continue with the next couple of videos.