Hello and welcome back to the Kelly Wallace certified pen test, your third Cup series.
We're going to talk about some Linux essentials or Linux fundamentals.
We're going to talk about important Linux fundamentals because Linux is at the core of ethical hacking.
If you want to be good at calling Linux, you must learn Linux.
The same could also be said of cyber security and system administration or network administration.
There are so many jobs that use names or so many things that use Linux, so many scripts, so many programs,
so many servers, so many tools that use Linux.
Many of the security tools and pen testing tools run on only Linux or are made specifically for Linux
or run better on Linux.
So that's one of the major reasons to learn Linux fundamentals.
Linux also powers the cloud, so it can be important for that application as well.
This is our outline.
We're going to talk about the women's file system.
We're going to talk about Linux file system folders.
We'll talk about the command line command line basics.
So Linux is based on the old Unix file structure, too.
So we'll look at the various Linux system folders and files that are contained there.
We'll also go over the command line and several the command line basics.
And we'll even throw in a few other bonus commands at the end of the module.
This is the Florida chapter.
So we'll look at the different unifying file systems for Linux, the command line, and also important
commands you should know.
So if you knew the Linux command line, you may find yourself wondering why there are so many unusual
directories, what they're there for, why things are organized the way that they are.
In fact, if you're not used to how Linux organizes files, the directories can seem pretty much arbitrary
with strangely truncated names, in many cases even redundant names.
Turns out there is a method to the madness based on decades of Unix conventions, though each Linux
distribution has its own quirks a majority conform for the most part with the file system, hierarchy,
standard or FH, as the FHC Project began in 1993.
And the goal was to come to a consensus on how directory should be organized and which files should
be stored where.
So the distributions can have a single reference point from which to work.
A lot of decisions were made.
About the directory structure and they were based on the traditional UNIX directory structures with
a focus more on servers rather than individual desktop users.
So and also the assumption that disk space was at a premium, so machines would likely have multiple
hard drives.
So Lennox uses the file system hierarchy standard or F as.
So these are the different owners.
This is not an all inclusive list, but this is a good chunk of them.
So first we have the bin or the slash bin and slash SBN slash bin and slash SBN directories are intended
for storing binary executable files, both directory store executables that are considered essential
for booting the system like the Mount Command.
So if you want to mount other folders and external devices, the main difference between these directories
is that the slash s-pen.
Directory is intended for system binaries or binaries that the administrators will use to manage the
system.
Slash boot directory.
This stores all the bootloader files, which is typically only grub, the Grand Unified Bootloader kernel
files and init runtime name and files.
It's often treated as a separate small partition so that the bootloader can read it more easily with
slash boot on a separate partition.
Your root file system can be used for more sophisticated features that require kernel level support,
whether it's an exotic file system, disk encryption or logical volume management.
LLVM.
Then we have the SC directory which will probably spend a lot more of your time.
The Etsy directory is intended for storing system configuration files.
So if you're looking for a service or change some type of networking process or other course settings,
Etsy is the first place to look.
It's also smaller and easier to backup directory that contains most of the customizations you might
make to your system or your computer at the system level.
So let's go ahead and look at the Etsy directory.
So I notice in here we've got a lot of different things if we can get it out to the screen.
So we've got Pearl, we've got PHP, we've got Python, we've got the nocturnal network manager is here.
We have the mice duo.
We have log logging definitions.
We have the the kernel.
We have the first tab file.
Lots of different things here, the Chrome tab.
So if you want to run a particular recurring tasks and jobs in your system.
And of course we have the Apache.
As well as the chromium browser, the lots of files in Etsy.
Let's look at
the bin directory.
We can see different binary files.
Here are the different domain.
A lot of the commands you might type like Who am I with?
Wireshark.
Update commands.
Traceroute.
Lots of different things are in this folder.
Then we have the SBN folder.
So a little bit different, but very similar stuff.
So let's talk now about the Home Directory.
So this is the location on the Linux system where the personal files are stored.
So each directory under home is named after a particular user's name and is owned by that user on a
server.
These directories might even store the email, assets, keys or even services that are running on certain
ports.
On desktop systems, your home directory is probably the main directory where users will interact.
So any desktop settings, pictures, media documents or other files users need to end up being stored
in their home directory.
It's one of the most important directories to back up, and it's often a directory that's given its
own partition.
Are giving home its own partition.
You can experiment with different Linux distributions and reinstall the complete system on a separate
partition.
When you mount the home partition, all your files and settings are right where you left them.
So let's look at the home directory briefly.
So we've got Kelly, which is the default account and we have user one end user, too.
So let's look at Kelly.
The screen and there's the home directory.
We can see the bash, our C file.
We can see the a few other important files.
Your documents folder, your downloads, your desktop.
Things like any session hours you might have.
So that's the home directory.
Then you have the lib directory or the library directory, the stores essential shared libraries that
the slash men and women need to be able to run.
This is also the directory where any kernel modules are stored.
So another directory we have is the US directory or the slash units are rectory.
This is stood for both UNIX source repository and also UNIX system resources.
So this is typically when you install additional software from your distribution, its binaries, libraries
and supporting files.
They go here in the U.S. or been or use our SBN directory and sometimes the US r slash lib directory.
When storage was at a premium, you would often mount this directory separately on a larger disk so
you could grow it independently as you added new software.
So let's briefly look at these directories.
There's a slash lib directory at the system D, but different versions of python postgresql.
Network time protocol libraries as your kernel modules.
As the US slash bin directory.
So if you got your pin.
Your pin command.
Among other things, and you have your OPPT directory.
So the debates between us are slash local and OPPT or something interesting.
They've been back and forth.
Essentially, both directories serve the same purpose, providing a place for users to install software
outside their distributions.
So the OP directory organizes a little bit differently.
It stores binaries in libraries in a shared directory.
So then you have the slash route directory, which is where the administrators personal files are.
It's owned and readable only by the user, and it's designed otherwise to function much like a home
directory.
But for files and settings the route user needs.
Many systems will disable the root user in favor of using sudo to get superuser privileges.
So this directory isn't used nearly as much.
And then you have the slash var directory, which is the place where a lot of your logged spaces are
stored.
A lot of variables that you might need by certain daemons.
So classic UNIX servers help this space that are premium and the bar directory was designed for storing
files that might vary wildly in size or might get written to frequently.
Unlike with slash user, which is read only the bar directory most definitely has to be rideable because
you're going to find log files, mail server information, or anything else that might come and go or
otherwise need to grow in size in unpredictable ways.
So at least with servers, if you had to pick a route level directory to put a large disk on the VAR
directory, it would be the first on the list.
And you want you want to have a drive that's better optimized for heavy rights.
So then we have the slash DV directory.
This is for device files, essentially unix, everything as a file.
So even your hardware ends up in the file.
So then we have mount and media file.
So Mount and media are more going to be used if you're adding a USB drive or a network file, share
mount or some other source, you need a place for them to go.
So the mount used to be a catchall for any amount of disk, didn't have anywhere else to go, but typically
now you want to use that for more network file shares.
The slash media directory is more for those things that are going to be mounted temporarily, like CD-ROMs,
USB drives and so on.
So the starting point of the hierarchical tree for the file system is called root, which is represented
by the slash character.
So the directory can of course obtain or contain subdirectories when it has only one root hierarchy
and it can integrate data from several disks.
But one of these just becomes the root and the others are mounted on directories in a hierarchy.
So mounting is essentially attaching an additional file system to a currently accessible computer.
And the different types of file systems or the hierarchical file systems are the next to the Z three
Annex D for the EC2 or second extended file systems.
The system for the Linux kernel.
It was designed by Remy Card as a replacement for the extended file system original.
Then we also have the Windows file system or the empty file system.
Which stores?
In a particular format is a proprietary Microsoft proprietary journaling system and has been around
since Windows 90 and is the default file system of Windows.
It is supported in other desktop environments and server operating systems as well.
Linux and BSD also have a free and open source NTFS driver.
Which is called NTFS dash 3G, which has read and write functionality.
Mac OS does come with a read only support for NTFS.
So because write support is not stable most of the time, if you put an end to best drive in a mac,
you will not be able to write to it, although you will be able to read from.
So when Linux creates essentially a new partition for every device or distance attached and it will
typically mount mount under HDTV, slash SD one or slash SD eight to.
So let's talk about the command line.
So the command line in Linux is the terminal or the terminal interface.
And it can vary from distro to distro.
So from the Linux console, originally, the console was actually a terminal plugged into a computer.
It provided an interface that was used to configure and control the computer and view the messages from
the operating system.
So in a Linux server first boots, it prints out status messages to the console.
So when you never seen that startup script, that text that comes before your operating system boots,
that's your terminal.
So essentially when you're interacting with your server, you're connecting that terminal to a program
running in the console.
So let's take a look at the Linux terminal and Kali Linux.
So if we open up our Kelly Linux distribution
and we already had a terminal open from looking at the file system, but let's go ahead and close it
down and exit out.
They've actually changed it now, so we're used to close it now.
There's a different type of command and that does happen sometimes and there are some shortcuts on certain
life distributions to be able to get to the the terminal.
Or we can click on the icon or we can create it here.
So this is essentially the terminal as most people use it.
It might be called ICS term or some other other thing in that case.
So.
The command line is essentially your Linux shell or your Linux terminal.
So the default shell provided in Linux is bash.
So the bash commands or the bash shell.
If you see a dollar sign, that usually means that you're in a user session.
If you see the pound sign, that means you are route.
So let's go in and look at our colleague Linux.
Notice there is a dollar sign in this case.
So I'm going to go ahead and.
Zoom in so it can be seen a little better.
So we're going to pull my command so that I'm currently logged in as the calling user and we can see
who's actually logged in.
What's the debris command or the who command?
Basically the same kind of thing.
If we want to sudo to root, we have to type in the password.
Our prompt changed to a symbol.
So that means we can now enter commands as an administrator or a root user.
So essentially if you're typing in a command into that terminal are connected to a Linux server, you're
essentially telling that Shell to run that program and print out whatever output it sends to the screen.
So it's always important to be aware of what level of permission you have in the shell, because the
only way to run commands as route has to be done via the command line.
So let's talk about some other command line basics and penetration tests.
You're most likely have show access only after a successful exploit rather than a graphical user interface,
especially if you're dealing with a cloud based server.
The cloud server may not even have a gooey interface at all.
So becoming proficient with the command line is essential for you to be successful as a security professional.
And of course, as we've mentioned, the command line in Linux is called the terminal.
And you can also open up a terminal with the control and t shortcut on the keyboard.
Charlie, of course, uses the bash file and it's hidden by default.
Notice that there's a period in front of it.
So if you just type, if you go into the directory here and we just type else notice there's no files.
But if we do a last minute shows us the hidden files and the bash dot RC and the bash dot original so
it can fit the bash.
The RC is the configuration file.
So add that to the screen.
We can see different variables that have been declared and different functions.
And so if we want certain commands to have aliases instead of having to type the full command, you
can do that here.
So the bass shell stands for the Born Again Shell, which is just a type of interpreter that processes
commands.
There are other kinds of shells, but Bash is the improved version of the shell, which is the born
shell, the original version.
So Shell scripting is how we write programs.
For the terminal to execute the command line can be used for anything on call, including triggering
an application, checking for network statuses or any other activity that can be done using the graphical
user interface.
So there's some basic Linux commands we want to understand to be successful with the command line or
be proficient with the command line.
All right, let's talk about some more basic Lennox commands.
We've got PWT, which stands for print or present working directory.
And Peter actually will show you the user in which directory they're currently working on.
And we have.
Also the last command to show what files in the directory you're in.
So if you're.
I'll switch over to our Linux desktop here.
And it clear the screen and print it and we'll see.
I'm currently in the home directory.
If we go to the main page, we can print the logical name.
We can print version information.
Just a basic man.
And of course the US command, if you just, you else was nothing else, you know, just give you all
the non system or non hidden directories if you do ls dash l you get a little bit of a different view.
You actually can see the bits that are set for permission in Linux, so you can see if it's a D in front
of it.
It's a directory.
If you do ls dash l a you get all the hidden directories and the hidden directories actually have a
period in front of them and you'll see.
They have different bits which we'll get into later when we get permissions.
But less is useful because it helps you list the file structure and if you forget how to use it, you
can do the main page and it stands for List Directory Contents.
You can have it list by columns if you want to do list, see,
so you can have it display in different modes.
You can have it.
Do you grouping directories together?
You can format in certain ways.
One of the different options you actually also have it print out the elements which can be useful if
you're doing.
Certain storage operations.
All right, let's go and switch back over to the slide deck.
And so that's Peter Beattie.
Unless very important, Peter Beattie is actually environment variable which stores the path of the
current directory.
So let's go ahead and do this if we do.
Echo dollar TWD.
It will actually do the same thing.
So let's talk about the CD command and the change directory command.
This is one of the most important and widely used commands in Linux.
Do you want to change to another folder?
Sure.
And they want to go to the downloads directory.
You can type CD space downloads or CD space the full path of the directory.
See is essentially in some ways the only way to check a log on headless servers.
So for newbies, it's one of those initial commands that you'll get your hands dirty with, or it's
very much similar to the CD command on Windows.
We also have the M, R and R MDR or the make directory and remove directory commands.
So if you want to create a folder and also remove folder, you can use these commands so you can create
multiple directories at once.
You can also set permissions for those directories.
So it's important to know that when you're a user executing that command, you have to have the right
permissions in the parent directory, or you also might get a permission denied error.
So let's go back over to our Linux.
Box.
And we'll go ahead and make directory.
Let's actually.
We'll call it new underscore.
Directory.
Let's say make directory new underscore directory to.
New Underscore Directory three.
So we can make multiple directories and we do the LS command.
We'll see that all the directories have been created.
Now what if we want to remove the directory from D.R.?
Let's say we want to remove directory number three.
Now we can do tap completion to partially complete the command.
And if we do the command again, notice that that new directory is actually removed.
So make directory and remove directory are important.
Let's look at the main pages so you can actually set arguments.
You can set it to verbose mode.
If you want a message, run it for each directory.
You can also integrate with Linux, the security enhanced Linux, or you can just output the version
information.
So we'll create a new directory for.
And it gave us kind of a running log of what's going on.
Should be dashed like.
There you go.
So you can see that this software is also licensed under the GM GPL license.
And it tells you a little bit about who wrote it.
So that's CD and make directory in our movie directory.
Now let's look at the arm command.
If you want to delete files.
You can delete individual files.
Let's go ahead and.
Look at the files we have here.
Let's go ahead and make a new text file.
Say, This is my new text.
File and I'm super excited to be learning Kali Linux pen testing, distribution and escape.
I'm going to write with.
Clear the screen and we're going to see that we now have a new text file.
We have new text.
Text, and we can actually just remove that individual file.
And we see that the file is now gone.
If you want to remove dash are.
And we want to remove that new directory.
Notice that the new directory is now gone.
Anything that was under it will also get removed.
So be careful with it or remove command.
If you do remove the r f, you can potentially remove recursively.
So our will remove references to objects from the file system where those objects might have had references.
So if you have a file with two different names by default as it is not removed directories generally
it works silently.
So you want to be really careful so you don't delete things as you want to.
Maintain.
So let's talk about the touch command.
So the touch command is used to create a file that can be used to create almost anything from an empty
text file to even a zip file standard Linux Command.
Which is pretty much.
Available with every distribution.
So with the touch command, let's go and look at the man page.
So you can change file timestamps.
So if you do use the touch command, especially if you get into forensics, you want to be careful with
it because you will change the file.
So if we want to touch a new file, we now have a new file.
And so from that we can manually run in the home directory, we can check this with the print working
directory and if we check the last command, we get more details about existing files.
So that's the arm command and the touch command.
So what about the man?
The Help page using the man page for a while.
So at the man page, if you forget how to use a command, you can type man and then the name of the
command like code in this case.
So sometimes there won't be a manual page for that.
But nine times out of ten there will be so.
Main page is short for manual page.
It's just a form of software documentation on UNIX and limited software.
And so things that are covered include computer programs, library system calls, sometimes standards,
conventions, even abstract concepts.
User might invoke command page by issue, issuing the man command.
A default man typically uses a terminal pager programmed more or less to display the output.
So you have to hit the spacebar to return more options.
So because man pages are distributed with the software, they document their more favorable means of
documenting software compared to other out-of-band management techniques like web pages.
There's higher likelihood for a matched with the actual features of the software to the documented ones.
It's for this reason that man pages are often referred to as online or an online form a software documentation.
Even though the man command does not require internet access.
Going back to the days when out of band manuals were the norm.
So let's talk about the copy command.
So the copy command.
Okay to copy certain files.
So it takes two arguments.
The first is the location of the file to be copied.
The second part is where you want to copy in that.
All right, so I've done the copy command and we're going to work on the next set of command.
So actually let's do a demo of the copy command first.
We'll copy the.
New text file we created to a new directory.
So let's go ahead and do that or close the browser.
You don't get rid of these notifications.
So we have the new file, that text.
And we're gonna give it the path.
We're going to it to home.
Kelly slash documents.
And there we go.
And change to the documents directory.
And our new file is there.
So magical.
Unless we can copy files from place to place.
Without too much difficulty.
So let's go to the next set of commands.
So copy also has some different syntax.
And usually do the copy command at the dollar sign prompts regular user.
Let's look at the move command.
So the move command, we can move files other places.
Or he can also use the MOVE Command to rename a file.
So let's say we want to rename the file.
You filed the text.
Particularly.
I have it backwards.
So we're going to the first part is the follow on to remain and the second part is the what you want
to rename it to.
And we're going to.
Now we have a new file that's been renamed.
So that's one use of the MOVE command.
We can also use the MOVE Command to rename the directory.
So let's go and make a new directory.
So there's a new.
We're going to move the new directory.
Make it new directory too.
So we do the command again.
We now have the new directory, so we can also use it to move a directory from one place to the other.
Let's move the source directory.
Is a new place for moving to Etsy.
Let's see.
When I moved to Etsy because.
You know.
Oh, it's called mediocrity.
That's my fault.
And if you go to the ABC directory, we'll see the new directory two is in fact there.
And there we go.
So we saw how the move came in and can be used to rename a file on all some directories.
We have a locate command.
Locate command is used to locate a file in Linux system, just like the search, command and Windows.
So this actually is useful when you don't know where the file actually is.
So let's go ahead and clear the screen.
So if I want to locate my new directory or new file.
What did I actually name it?
I can't remember.
Let's see.
So we call it new father text.
Let's go ahead and clear out.
It's going to change back to the ETSI directory.
It doesn't know where it is because I don't think it actually has the.
So yeah so location.
It'll look for some different things you can do regular expressions to do a lot of different commands
will locate.
And most distros will come with the.
Proper syntax.
So now we have the Echo and the cat command.
So if we want to actually echo something to the screen, we can even send it out to a file.
So.
This case.
We're going to echo.
Hello.
My name is Chris.
When a cat that out to do that text file.
We'll see the new DOT text file appears.
Because the directory ran.
And there we go.
And there you go.
There's the file, the cat command we've been using quite a while.
Cat is short for Concatenate, and it's one of the most frequently used commands.
And Linux allows us to create files, view the contents of the file or redirect output, so on and so
forth.
So if we look at the cat command, we can see we can print on standard output.
We can cat in eight files.
We can.
Show tabs and show non-accredited characters many different things.
But then we have different text editors.
If you're one thing that you're going to do in Linux, you're going to do creating editing text files
among the common tax reform.
Whether you're on Linux or Unix, if you're programming, developing Web pages, sending email, writing
letters, configuring your environment, you're going to eventually work.
With text editors.
It's a very important skill to have.
Unchanged directory to the home directory.
One of the most common text editors is VII, or which is now called them or VI approved.
And it has two different options.
So then there's backwards compatible VI.
There's also g m, there's g view.
There's all kinds of different things.
So there was a very powerful text that you can use, but it does have a kind of a steep learning curve.
Lots and lots of different commands.
There's even a gooey version of them.
But it may not always be installed on certain Linux distributions.
So depending on the repository you're in, you may not have access to it, but I will always generally
read the default to them.
So there's also Nano, which is another common text editor.
The Nano is another editor inspired by Pico.
So it doesn't always wrap blind.
So if you want to have your text editor look like some of the other text editors, you can do that.
But it works very similar.
Let's go ahead and then I'll.
My new text text.
So we created a new text file and say, this is the new text file and it's a bit easier to use.
And then.
We're done.
We want to write it out to a file so they control.
Oh, we'll give it a name.
We know actually what direction we wanted to go to.
They wanted to the calendar directory one to downloads.
And many different options.
You can do this with.
If you need help, you can actually display the help.
So a lot of different options with Nano and them.
There's even a one called Jab.
So we can manage an.
So Jeb may not always be installed.
And Sonam's text editors get deprecated.
Let us be aware, not just because it works on one distro may not work on others.
So this is definitely.
Simpler than now as far as the format.
Of course, then we have pseudo.
Pseudo is an important command.
It's widely used and when it stands for super user do.
So if you want to run a command of villages, you can use sudo command.
So if you want a pseudo to root on a pseudo the password, change the password, update passwords you
want to switch users.
Many cases will use pseudo.
There's also the union command, which is designed to show information about the system.
Your Linux distros running.
So let's go ahead and.
Exit out on a pseudo S2 or type in the past for calendars now route.
An exit back out to the man pseudo.
And it's going to give us some options.
So basically sudo allows us to run commands as another user and the policies and security policies will
determine what permissions you have.
So we can do lots of different things with pseudo.
If you're going to edit the SC pseudo file.
You want to use the visceral command.
If it's there.
Some distros as they are newer, they may not have the visual command.
So just be aware that the process may be different depending on the discharge over the next that you
have.
So you name Carmen.
So we want to show information about the system that's upcoming on the terminal.
So we're running Linux, Kali Linux 5.5, AMD 64 number one and it says what builds for running?
So then we have the apt get package manager.
So an ending on what we're running in.
We may not have access to full.
The same full list of applications.
So we want to install something we don't have.
We're going to do a pseudo app, get install.
My case, I'm going to install Emacs.
Let's try to get it.
So they've taken it out of the classroom, which is does have the time.
So just be aware that just because APT works now, it may not work on certain commands later.
So we want to get updates and you want to go out and grab the latest and greatest updates from the repositories.
This is a good practice too, because you might have to update your OS to make sure you have the latest
and greatest tools.
He also can do an apt get upgrade which will upgrade to the latest and greatest version and that will
take some time.
So he knows it goes out to Cowley.
Download the Cowley Rolling Repository and it's going to go update all the packages that are available.
I'm calling.
Once you do an update, you may want to do an app to get auto remove.
Or an apt get clean if you have a failed install.
Let's go ahead and go back to the slide deck.
So with apt get you have to do pseudo.
Otherwise it may tell you are you root and it may not work.
So then we have the change mod command or the C-H Mod Command.
C-H Mod is essentially the way we make files executable in Linux, and you can either do it from octal
notation or you can do it from a setting different bits on a file.
So if I want to change stands for actually change mode.
But.
A numbers and letters will distinguish between who is actually as what permissions.
So let's go ahead and look at cloud permissions and Linux.
Once it's done updating, we'll go in no company tab just because save time.
Well, let's stop missions.
And what if I want to change?
So right now, the new father text has a certain set of bits.
These are the bits right here.
So it has user bits, group and has owner bits.
So let's go ahead and do a C-H mod.
I'll make everything rideable and everything executable.
So notice I'm not pseudocode so I will not have permission to do that.
If i sudo to root and i have permission.
And that's what I do, that the file color syntax will generally change.
In this case it doesn't, but some by extension, will have a red color set or executable.
So this is change months.
Seven, seven, seven.
What does that mean?
Well, that means I have set, read, write and execute.
So those are the best you can change.
If I want to change my mind.
Yes.
Execute.
That particular file.
I could do that and I've taken away executed from all the different groups.
That's important to understand.
C.H. Montgomery.
Then we have the hostname commands.
We want to change our view of the hostname and IP address.
This is actually Kelly.
Let's look at the man page.
So this will show or set the hostname.
This will also.
Show or set domain names.
So we have several different options here from within the.
This menu, so might send it a fully qualified domain name.
It said it is an IP address.
Lots of different options.
I want to change the name from the system.
I've now changed the show's name to Hatbox.
All I had to do was change the name.
And there we go.
So then of course we have the variable pane command and commands can be useful because this allows us
to check our connection to the server.
We can ping much like we can in our windows system.
I can thank Google and I will continue paying until I stop.
So if I want to just paying a little bit differently, I can use the main page and see what other options
there are I can take with IP version or IP version six.
I could even have it be an audible.
I can have it print the timestamps if I want to ping flood something.
It's going to flood Google things and Google most likely come back and not allow it to go.
So I want you to ping.
What IP versus six?
I can do a pinged at 6:00 on.
It says the network is unreachable because they don't have IP six enabled.
So I can actually tell it the number of pings or another number of hops to go that are having it go
continuously.
I could change the time to live with just how many hops it will go before it is dropped.
So playing is an important command for Linux.
Other useful commands.
We have the find command which will find files or directories.
I want to find Stark's text file.
So I found my new file by text.
And then I want to see how much memory is free.
So the free command will display not only the amount of free memory, but also the use memory and swap
space as well.
And we have the deaf command.
Do you have command?
We'll show you.
How much disk space is free.
We have a lot of space left on your hard drive.
Or if you're running out.
You can also have it print out the AI nodes.
You can have a print out the different partitions that are there and how much space is taken up.
And see, I have 13% used on the partition.
64 gigabytes.
So let's go to the ID man.
So the user we've already talked about the identity of the user with the groups they belong to.
So my current user is part of the group, part of the CD-ROM group, student group.
Many other different groups right away.
It's gotten cashed out of the password file.
So let's do.
Switch to user one.
And I can't when I set the password to.
I have to go back and change the password because I can't.
It was basically you'll be able to see the identity of the user, the message which can review kernel
logs.
But you had to be sudo to do it.
You can see all the messages coming back from the colonel.
You can also look at the different hardware on the Linux system with the PCI command, which is also
good for other versions of Linux too.
So I don't see what type of processor or whatever sound card of a video card, so on and so forth.
You can also list all the USB devices.
So this is a virtual rehab on your physical systems running Linux, you may have some other options.
Then you have the less GCM CIA.
So this case I've found.
So they've taken it out because it's PKM say PKM CIA cards are not as common.
So maybe another process using Arial.
Yeah.
So we got a locked file that's going here.
That's okay.
But PCMCIA cards, there are some other useful commands
such as process management.
So on Linux you have the PS command.
Yes shows all the processes currently running in the A which is a more detailed version.
You can kill processes.
So let's say I want to kill.
P.S. a U.S..
So I usually have to have the process name.
And if you maybe you want to send the process to the background.
Somebody is Wireshark.
There we go.
So.
Gentlemen, this will work.
But because Caligula makes in the new version has changed things, it may work a little bit differently.
We have the effigy.
So you take the background job to the foreground.
And show background processes.
So in summary, we talked about the one file system.
We talked about Linux file system folders.
We talked about the command line.
We talked about command line basics.
We looked at some different basic Lennox commands and we looked at other useful Linux commands that
are there.
So I hope you enjoyed this particular module.
We covered a lot of material, but there's a lot of useful commands that you will find that will help
you in using Kelly Linux as well as other Linux distributions.
So we'll see you in the next module.