Original subtitles

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Okay, now that we had a quick overview 2

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of Kali Linux, I want to spend some time talking 3

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about the Linux terminal. 4

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So you can access the terminal 5

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through this application right here, 6

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so if we click on that, 7

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it'll open the terminal window for us 8

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and as you can see, all it is 9

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is a black screen where you can type commands. 10

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Now, the Linux terminal 11

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is actually very, very powerful 12

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because it can be used to do anything 13

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that you can think of really. 14

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A lot of the applications in Linux 15

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that have a graphical interface 16

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where command prompt programs first 17

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and then people made a graphical interface for it. 18

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So a lot of the time, maybe the graphical interface 19

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will be buggy or crash 20

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and the terminal program will still work. 21

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Also, a lot of the penetration testing tools 22

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do not even have a graphical interface. 23

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A lot of them can only be used 24

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throughout the terminal. 25

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Not only that, but in many scenarios, 26

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you might only have an SSH or a command prompt access 27

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to a machine. 28

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So you need to know how to use this command prompt 29

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in order to achieve your goals. 30

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So throughout the course, 31

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we're gonna be using the terminal a lot 32

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and that's why I want to spend some time 33

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just showing you the basics of it 34

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and making sure that you're gonna be comfortable using it. 35

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Now, the basic idea is you type a command 36

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and the result will be displayed for you on screen. 37

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So let's have a look on a very, very simple command 38

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which is pwd. 39

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Now, this command prints the current working directory, 40

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hence the name pwd. 41

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So if I hit Enter, 42

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you can see it's printing /root 43

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which means right now I am in the root directory. 44

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So basically I am in here. 45

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This is the root, it's home. 46

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So if I do ls which is a command 47

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to list all the directories and files 48

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in the current working directory, 49

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we should get all of these directories 50

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that we see in here. 51

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So if I hit Enter, 52

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as you can see, I can see all these directories 53

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in the current working directory. 54

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Now, another very useful command 55

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is the cd command. 56

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This command allow us to navigate into another directory. 57

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So for example, let's say I want to navigate 58

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into the Downloads. 59

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All we have to do is type cd, 60

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followed by the name of the directory 61

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that I want to navigate to. 62

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So I'm gonna type Downloads. 63

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Now if I hit Enter, 64

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I should be inside the Downloads now. 65

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So if I do pwd to see my current working directory, 66

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you'll see that it's saying I'm in root/Downloads. 67

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So if I do ls here, 68

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it should show me all the directories 69

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and files inside Downloads. 70

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So if I do Enter, 71

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as you can see, I have a directory 72

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and a file in here 73

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and these are the exact same files 74

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that you'll see if you double click the Downloads here. 75

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Now, if you want to go back one directory, 76

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so similar to pressing the back button in here, 77

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all we have to do is do cd, 78

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again the command to change the working directory 79

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followed by .. 80

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And now if I do pwd, 81

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you'll see I'm back in root 82

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and if I do ls, 83

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you'll see all the directories and files in root. 84

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So that's all good. 85

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And there's actually a huge number of commands 86

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that you can use. 87

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So I'm going to include a link 88

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in the resources of this lecture 89

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of all the Linux commands that you can use. 90

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You don't need to know them by heart. 91

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We're actually gonna be using a lot of them 92

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throughout the course 93

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so you're going to naturally learn them 94

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as you go through the course. 95

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Now, if you are using a command 96

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and you're not sure about how this command works, 97

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you can just use the man command 98

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to display the manual of this command. 99

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For example, we've used the ls command here 100

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to list the files and directories 101

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in the current working directory. 102

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But if I do man followed by ls, 103

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this basically means I'm requesting the manual of ls 104

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so I'm asking how can I use the ls command? 105

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So if I hit Enter, 106

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you'll see I'll get a screen similar to a text file 107

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and basically it's giving me a lot of information 108

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on how to use the ls command. 109

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So you can see that it's telling us 110

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that this command will list the directory contents. 111

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You can see the way it works by typing ls 112

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followed by the options followed by a file 113

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if you want to run it on a file. 114

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You can see a longer description 115

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of the command. 116

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And then, you can see all the options 117

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and the arguments that we can use with this command. 118

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Now, in Linux, most of the time, 119

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the options will always follow the same syntax. 120

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So you either use dash letter or dash dash a word 121

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to specify the argument. 122

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For example, in here, the -a and --all 123

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will ignore entries starting with dot. 124

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So if you keep going down in here, 125

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you'll see all the options and arguments you can use 126

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with the ls command 127

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and we have another example here. 128

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We have the -l 129

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which means it's going to use a long listing format 130

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which will display more information 131

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about the files in the current working directory. 132

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So let's have a look on that. 133

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I'm gonna press Q to exit this 134

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and then we're gonna do ls as usual 135

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and since we read the manual, 136

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we know we can do -l to see more information 137

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about the files 138

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and if I hit Enter now, 139

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you can see I'm still getting the same directories 140

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but it's also showing me the permissions, 141

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the users, the date created and so on. 142

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So you can use the man command 143

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on any command you want, 144

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not only on the ls. 145

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So you can use it on the pwd, 146

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you can use it on the cd 147

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or any other command 148

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and it'll show you a full description 149

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or the manual page of how to use this command. 150

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Now, I'm going to clear the screen 151

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by typing clear. 152

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And the next thing that I wanna show you 153

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is the --help. 154

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So this is something that you can use again 155

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in almost all commands and all programs in Linux. 156

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So you can just type the program name 157

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or the command name followed by --help. 158

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As you might think, 159

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this will show you a help message telling you 160

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what this command is 161

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or what this program is, 162

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the arguments that it takes, 163

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how to use these arguments 164

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and examples at the bottom. 165

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Now, another useful thing with the terminal, 166

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so I'm gonna clear this again 167

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is the arrows. 168

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So you can press up to go up to see all the commands 169

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that we executed before 170

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and again, you can go down to see to navigate 171

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between the commands that you executed previously. 172

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You can also use the Tab for autocomplete. 173

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So again, let's do ls 174

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and you can see all the files 175

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and let's say we want to go into Documents. 176

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So we can do cd followed by Documents. 177

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You can type Documents 178

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or if you're lazy like me, 179

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you can just do Doc and press Tab 180

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and as you can see, it's automatically completing 181

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the rest of the word for me. 182

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So this is something that comes very, very handy 183

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when you're using the terminal for a long time. 184

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Now, what I also wanna show you 185

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is how to install programs in Kali from the terminal. 186

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So first, I'm gonna clear this. 187

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And the first thing that you wanna do 188

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is update the sources where Kali can search 189

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and download programs from. 190

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So we're gonna do apt-get update. 191

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Now apt-get is the name of the application 192

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that allow us to download and install programs 193

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and we're saying update 194

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because I'm saying that I want you to update the list 195

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of all the programs that I can install. 196

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So I'm gonna hit Enter 197

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and you wanna make sure that you have internet connection 198

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when running this. 199

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And as you can see, it's telling me that it's done. 200

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And now, we can go ahead and start installing applications. 201

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So the first program that I wanna install 202

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is actually a terminal program, 203

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so similar to this one 204

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but it allow us to have multiple terminal windows open 205

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in the same window. 206

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So in order to install a program 207

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through the command-line, 208

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we're gonna do apt-get which is again, 209

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the name of the program that allows us to install programs 210

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on the system. 211

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We're gonna say that I want to install 212

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and the program that I want to install 213

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is called terminator. 214

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So very, very simple. 215

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First of all, we're typing the name of the command 216

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which is apt-get. 217

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We're saying that I want to install 218

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and the program name that I wanna install 219

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is called terminator. 220

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So I'm gonna hit Enter 221

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and this is going to download and install terminator for me. 222

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So you can use the same command to install any program 223

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that you want, 224

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you just need to replace terminator with the name 225

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of the program that you want to install. 226

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Now, I've already downloaded and installed this before 227

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so it didn't ask me to confirm. 228

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But if you're running this for the first time, 229

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it might ask you to confirm 230

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whether or not you actually want to install this program 231

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so all you'd have to do 232

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is press Y from the keyboard and hit Enter. 233

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Now, as you can see, it's done 234

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so if I go to my all applications in here, 235

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and just type terminator, 236

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you can see that I have it here. 237

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So I'm actually gonna drag it 238

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and put it in my dock so I can access it easily 239

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in the future. 240

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So now I can just click it in here. 241

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And that'll open terminator for me. 242

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Now, this is another application 243

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that allow me to run commands 244

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so it's exactly the same as this 245

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so again, I can do ls and pwd. 246

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The only difference is with this one, 247

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I can actually right click 248

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and click on Split Horizontally, for example, 249

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and this will split the same screen into two screens 250

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where I can run commands at the same time. 251

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So I can have some commands in here, 252

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and I can run commands in here. 253

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And then I can even split this more 254

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if I want again vertically 255

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or horizontally and as you can see, 256

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I can have as many terminal windows as I want 257

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and this'll be very helpful in the future 258

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when we'll be running a number of programs 259

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and a number of commands at the same time.