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[No audio]

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Navigating to file system. Of course now you know a

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lot about a file system. Now we need to know how

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are we going to get into the file system? What are

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those commands that we really need to learn to

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actually go from one directory to another, get

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their file contents and find out which directory

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we are in. When navigating a Unix file system, there

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are a few important commands. Again, the number one

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command is cd which stands for change directory,

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second one is pwd, which is print working

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directory which tells you which directory you are

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currently in, and the third one is ls, which

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stands for listing which lists the contents of

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your directory or folder. cd stands for change

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directory, pwd stands for print working directory,

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and ls stands for list. Now let's look at the real

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example. I'm going to start with Windows because

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the reason I compare Windows and Linux all the

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time is because it will be a lot easier for every

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one of you to really understand the concept behind

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it. Because we actually work on Windows almost

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every day and we scroll through everything and we

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click through everything and we don't really

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realize how experts we have become. So if you

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really need to know Linux, there should be

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some comparison with Windows that I will be

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doing. So let's look at an example of Windows.

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Okay, so I have the C drive, which in Linux is

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what is the C drive for Linux is slash. When I

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want it to go into this a C drive, I will just do

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double click, and the folder comes up. And when I

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want to go into Program Files, I'll to double click,

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[No audio]

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and the folders comes up, and so on. And if I want

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to go into Windows directory, I'll just double click.

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In Linux, let's go to the Linux

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machine, I remember our Linux machine, the first

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thing I want you to do of course is become root.

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Meaning you are as yourself right now, how do you,

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how do you know you are yourself, is because first

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you see here on your prompt, you'll see your name.

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If you just still want to know your name, you

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could just type whoami, and you will see your

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username. When you become root, you have to

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type su, which means switch user, and just dash enter.

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[No audio]

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Put a new password

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[No audio]

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Okay, so you have this message that will tell you

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the last time you became root was this date, this time, and so on.

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Anyway, let's do clear, let's clear this, so

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I'm going to clear the screen. So now when you are

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in a directory, how do you know where you are. In

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Windows you can tell right? You could tell you are

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in computer local drive in Windows, it's up right here.

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But in Linux you don't know so the command that

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you're going to need is pwd. This is what, it's

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going to tell you that you are in this directory.

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[No audio]

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If you want it to go into a different directory,

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let's say you want to go to slash, which is slash,

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slash is the primary or the parent directory of

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all directories. So you type cd, which stands for

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again change directory space slash, you hit enter.

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Once you hit enter, how do you know you are in

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that directory? Again you type pwd, and it will

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tell you you are in slash directory. Now what's

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inside of this directory, we need to see that. In

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order to see that you have to type ls option l, and

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it will tells you all the listings of the

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directory and folders and files that are inside of

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this directory. In Linux, in Windows, when you are in

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My Computer you double clicking on a folder. Let's

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say you're clicking on Program Files,

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[No audio]

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move this around, and you click on any other folder, let's say

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Dell. So you notice you're just double clicking it,

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and it is taking you to that directory. In Linux,

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you don't have that. You don't have clicking.

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So what you need to do is you need to do cd. So

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you are already, what directory you are in, you are

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in root, and let's say if you want to go to a

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directory called let's say boot,

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so cd boot, boot,

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and there you are, you are in boot. Now let's say in

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this example you want to come here, you already

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see the listing of what's inside. How do I know

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the listing in Linux? All you have do is run a

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command, it's not that easy. There you go, it

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tells you this is what you have inside. By the

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way, some of the lines are chopped up a little, so

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I'm just gonna make this a little more bigger.

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[No audio]

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Okay, so you're gonna see anything that starts

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with dash, right here, it means it's a file,

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anything that starts with d, it means it's a

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directory or a folder. I want to go back to my

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root directory, but before I go back, I wanted to

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know where I am. The command is pwd, you we are

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in boot, and I want to go to slash root again.

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There are two ways you could do. You could do

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either cd slash, it will take you to slash

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directory or you could do cd.., which will

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take you one step back, one directory back. In

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Windows, how do you do that? In Windows, you could

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simply just do, you could simply press

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the back button, back button, and there you go. You

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have all that. Also, in Windows, you notice you are,

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when you double click once it is doing three

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things for you. You double click once, that is

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doing cd for you. Then automatically it's listing

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all the directories inside it's doing ls for you

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already. And now how do you know which directory

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you are in, right here on top that's how it tells

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you which directory you are in, and so it's in Windows you doing

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three things in one shot. In Linux, you actually

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have to use all three commands, one by one to see

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the same thing as you want to see in in Windows.

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So let's say if I want to go in etc, and I

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want to go into another directory which is etc

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sysconfig. So I am two directories in. How do I

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know? pwd, print working directory. It tells you, you

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are an /etc/sysconfig. Now if I wanted to go back

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to etc directory, what I would do cd.., and

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confirm if you are in etc directory, you do pwd,

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and there you go. What if you want to go one step

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back again cd.., and where you are, you

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are in root, there you go. What happened if you

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just type cd and hit enter? Okay, it did work

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because we got a prompt back we didn't get any

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error. But which directory are we again, we are in let's

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check, we are in slash root. Why, because we are,

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who we are, whoami. We are root, we are logged in

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as root. And root directory is slash root. So

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everyone, these three, first three commands that you

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really need to learn in order to navigate the file

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system. Without these three commands, you cannot do

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anything in Linux. So what are the three commands

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really quickly? First one is cd. Let's go to home.

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that's it. What's inside the home. Let's type ls

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-l. You forgot which directory you are in,

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just type pwd, you are in home. If you want to go

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to a different directory, let's say you want to go

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to, I want to see what's inside of slash. So I will

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type slash and what's inside of it, ls -l.

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These are the directories. I want to go into

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each of these directories and find out what's

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inside of let's say, I want to go to var. I hit

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enter, what's inside of the var.

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These are the directories, different type of directories. I want to go to

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file, a log directory right here. So I'll do cd

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log. What's inside of log, I have to do ls -

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l again. These are the files and directories

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inside of log directory. Okay. All right, I forgot

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where I am? where I am, pwd, /var/log, or if I want to

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go back to slash directory, you could do dot dot,

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then dot dot again, or you could just do simply cd

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slash and now where you are, you are in slash.

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Alright, so this concludes our lesson and I hope

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you have pretty much a very good idea about cd, ls,

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and pwd commands. As a homework, I would strongly

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recommend you to log into your Linux machine, go

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to cd slash, then ls -l, and I want you to go

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into each of these directories one by one,

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subdirectories, come back from a directory, find

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out the listing of the directory, and then you will

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find out exactly how to navigate the system.