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Instructor: Okay, so we know how to find our way

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to the desired directory in terminal,

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but what if we need to create a file

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or a sub folder in another directory?

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How can we do that?

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Well first let's open up our terminal.

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And by the way, another way that you can open terminal

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instead of right clicking and going open terminal here,

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is going up here to this icon which says,

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terminal emulator and clicking on it.

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By default, this will be inside of your home directory,

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which we know to be this sign.

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And if we type the PWD command,

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we get slash home slash Mr. Hacker directory.

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We know that our desktop directory

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is also inside of this directory, so let's go there.

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CD desktop, press enter,

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and now we are in the desktop directory.

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Let's get back to the files.

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To create a simple empty file,

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we can use a command called touch.

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If I simply just type touch file

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and let's call it file one, press enter.

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This will create the file named file one

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and it'll have no contents inside of it.

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We can also see that file one has been created

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as it is right now on our desktop,

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since we created it inside of the slash desktop directory.

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And if we also type ls, we can see that the file

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is in our desktop directory.

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To make sure this file is indeed empty,

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we can use the command cat

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and this command, once executed on the file,

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writes out all the contents that are inside of that file.

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Let's try it out.

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So we specify cat and then file one,

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press enter, and this will give no results

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since as we already mentioned,

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the touch command creates empty files.

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If we want to, for example,

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put something inside of that file,

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we can use a command echo.

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You simply just type it like this, echo

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and to put something, you specify after the echo,

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let's say today is a really good day.

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So we specified an entire sentence

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and all we need to do

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to put this sentence inside of this file,

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is to specify this arrow to the right

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and after it specify the name of the file

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that we want to put this sentence in.

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So echo, today is a really good day,

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into the file one, press enter, and if we cat it once again,

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with the cat command, so cat file one.

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We will see that now it outputs exactly

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what we've written to that file, using the echo command.

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Okay, that's all good, but there is an easier way

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and more practical way to do all of this.

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We can use a text editor

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to write things inside of a file

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and an easy text editor that we can run from terminal

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is called nano.

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So let's try to do the same thing we just did using nano.

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If we type nano and after nano

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comes the name of the file that you want to edit,

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and since we want to edit a new file

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that we haven't created yet, we can simply just type name,

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let's call it file two and press enter.

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This will open this empty window

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where we can type anything we want.

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We can type file content here and it can be anything.

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We can type for example text here,

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but we could also type code if we wanted to.

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Let's start with text first.

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Let's write just Hello World as a text.

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To save this we press control O together, then enter to save

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under this name, and then control X to exit the nano editor.

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If we now type cat and then file two, and by the way,

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we can notice that file two has been created

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along file one on our desktop, but if we cat file two,

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we can see the output of Hello World.

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So we manage to do it only using one tool

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which is nano, instead of using two tools

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which are touch and echo,

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but I also mentioned we can do the same thing with programs.

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For example, how can we create

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Python program using nano and terminal?

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First we need to open a file.

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So let's type nano and then file three dot py.

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And in this case we add dot py,

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because that is an extension for Python programs.

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Then inside of it, after pressing enter,

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we're going to run a simple command

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which is print and then Hello World between the quotes

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and you will see that some stuff changes colors.

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This is because the nano editor recognizes this

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as a Python program.

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What we did right here,

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in case you're not familiar with Python,

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is we just ran a simple function that will print out

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the string that is in between the quotes.

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So this will just print out Hello World.

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Let's save it with control O, then press enter

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and then control X to exit.

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And luckily for us

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Python is already installed in Kali Linux.

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So all we need to do to run this program

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is to type Python three and then the name of the file,

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file three dot py,

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press enter and the program will execute.

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Here it printed out Hello World, cool right?

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You'll also notice that the icon

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is different than these two icons.

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This is also, once again,

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because this is recognized as a Python program,

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it even has the Python icon.

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Now that we know how to create files,

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and execute Python programs, the next question would be,

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how can we create directories.

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To create a directory, we can use the command mkdir,

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which stands for make directory.

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To check it out, let us run mkdir

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and name a directory folder.

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So press enter, and if I type ls,

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we will see that we got our files as well as a directory,

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which is different color and it is called folder.

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Remember we differentiate them by color and also

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if we try to change directory to the folder, it'll work.

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It'll even give us the path of slash desktop slash folder.

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Great, in that folder you can do pretty much

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anything you want.

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You can create sub folders or create files.

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Whatever you want to do, you can.

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To move for example, our Python program

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from the desktop directory to our folder directory,

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we can use command mv, which stands for move.

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We must first navigate back to desktop directory.

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So let's do it using cd

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and then two dots, to go one directory back.

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And from it we run the command mv, file three dot py,

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into the folder.

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So we specify and move.

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Then the second parameter is what we want to move

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which in our case is file three dot py.

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And the last parameter is where we want to move it.

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We want to move it inside of our folder,

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so press here enter, and you will notice

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that the file three dot py disappeared

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from our desktop directory.

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We can also check that by typing ls,

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and notice that our Python program is no longer here.

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But if we go to the folder directory and type ls here

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we will see it here because we moved it.

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Here it is file three dot py.

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Now this is a handy command and you will use it a lot.

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Besides moving the file, we also want to see,

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how we can copy a file

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and we can do it using the cp command.

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This does the exact same thing as move command,

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but it doesn't move it from original directory

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to desired directory, it just copies it.

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So let's try to copy file three dot py

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and call it file four dot py.

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If I typed cp, which stands for copy, file three dot py

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and I type file four dot py, right after it.

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This will create an exact copy

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of our file in the same directory.

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If I press enter and type ls, here it is,

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we got file three dot py and file four dot py.

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If you want change whether they're exactly the same

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we can cat the content of file three dot py,

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and cat the content of file four dot py.

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And we can see they're both the same Python programs.

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And last command that we want to cover

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regarding files is the command rm.

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This command deletes files and directories.

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And let's say we try to delete file four dot py.

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That is our copy of our Python program.

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We can do it by typing rm and then file four dot py.

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Now be careful with this command,

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since once you delete the file,

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there is no trash bin where you can retrieve it.

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It is gone.

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If I type enter and type ls,

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you will see our file four dot py is no longer there.

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Okay, but how do we delete a directory?

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Let's first create a directory

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inside of our folder directory.

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And to do that we type mkdir and let's call it folder two.

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Folder two is a sub directory of our folder.

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If I type ls, here it is.

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And let's say we did create this directory by mistake

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and we want to delete it.

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Can we use rm, folder two?

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Well, we can try it.

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Hmm cannot remove folder two and it will tell us

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that it is a directory.

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So how do we delete it?

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Well, we'll remove it in the same way we remove files.

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We just add an option at the end of the command.

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So type rm, folder two

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and then at the end add space and then dash r,

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press enter and this will delete our directory.

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Also, double check what you're deleting

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with this command since if you go to our slash directory,

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which is directory containing all folders

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and files in system,

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and if you were to type, for example, in that directory rm,

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then the star sign and then dash r, this command

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would delete entire Kali Linux machine

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with all of its files.

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So always pay attention

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what exactly are you deleting in Linux

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and from which directory are you deleting?

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Since inside of the Linux

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you will not be stopped in deleting anything you want.

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You can easily delete a crucial file

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for the operating system,

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and make your Kali Linux machine unworkable.

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That is also a reason why we are practicing

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with virtual machine.

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So let's, oops.

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I actually ran this and you will notice that the results

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of this command, if I type ls,

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now our folder is completely empty.

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So I actually ran this by mistake and keep in mind,

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if I actually ran this from the slash directory,

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which is our route directory,

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I will delete entire Kali Linux system.

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For now on, it is good

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since I only deleted our Python program

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so it is not a big deal.

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Okay, great.

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We learn bunch of the commands in this lecture.

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Now I got the practice test for you

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that you can try to do for the next lecture.

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Inside of our folder directory,

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since I deleted my Python program,

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I want you to create the file three dot py, once again,

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you can type anything you want inside of it.

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You can use the print Hello World statement that we used.

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And what I want you to do using the commands you learned

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in this video is to copy that file

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in the desktop directory from our folder directory.

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So you create it inside of this directory

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and I want you to copy back to the desktop directory.

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A hint is that it can be a little tricky,

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once you copy file from some directory to directory.

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Anyways, just try it,

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and we're going to see the solution in the next video.