2.2 Useful Commands (KL)

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2 hours 9 minutes
Video Transcription
Hello and welcome to this Callie fundamentals lesson. I'm your host, Robert Smith, and I'm excited to be here with you today. So we've gone over some things that commands to navigate the file systems and, you know, very high level overviews of permissions, things of that nature. But you may be wondering there's
still a lot of commands out there. There's some things I may not know,
You know, What are some additional things that I could learn that will help me to get around Lennix and Callie and things of that nature? Well, today we're going to jump into those things. We're going to get some basic understanding of some useful commands, and we're going to see how those commands could be used
and, you know, again will continue to build on this foundation that we've put together
and go from there. So I'm going to go ahead and bring in my copy of Cali that I've installed here and you'll see that I've got a terminal opened up and we're currently in the desktop folder. And so
with that in mind, I've got a few things I wanted to show you.
you may be thinking I have an Internet connection. I can look up commands and understand what they do. But what happens if you don't? Or what did you just want to see? You know, a quick, easy look up of, ah, command or something like that? Well, I'd like to introduce you to the man commander manual. So when you type man and a command like Ping, let's say
it pulls up a bunch of information.
And as you can see here, it gives you the name of the command at the top of quick synopsis that gives your short description some options. And as you scroll through
down towards the bottom of all these different things that it provides,
it's got a packet, details and some additional information. So a lot of cool stuff there. Now there's multiple ways to use this. We can hit Q. And that takes us back to our desktop. Here. Do quick, clear to bring that back up.
Now we talked about catacomb, Captain eight. So you'll see over here to the left. I've got this hello bash file that I've created. If I type cat
and do hello
shows me the output for that file. So as you can see here. I've got some some line that I've written here for starting a bash script. And then I use this command called Echo. So you might be wondering what is echoed. Do what does that mean? Well, if we do man echo
like we were looking at earlier,
as you can see, it displays the name, gives you some descriptions. It says here displays a lot of text. This could be useful in for writing a bash script and we need an output. Or we wanted to reference something and produce an output from, like the system or something of that nature. We can do that
using the echo command. So that's gonna be useful for you when you start working on scripting and things of that nature
and you're jumping into, you know, trying to make some more complex ways of doing things or simplifying things and things of that nature. Now
you can easily use leaf pad down here
and edit texts and do things of that nature and edit files. But let's say I'm here on this desk top folder, and I just want to jump straight into that textile or that bashful Aiken do Nano and Hello
and bam! There we are. I've got my text editor open. Now there's several different types of text editors that you can use. I like to use Nano. Some folks like the eye of some other things like that. But in this case, this is what I like to use now is you can see here a type echo and then hello world
Let's say I want to make it a little more exciting and happy So I do
Hello World in two exclamation points here on the end. As you can see down at the bottom, it gives you some commands that you can use. You typically hold control and hit the letters. All hit control. Oh, to write out and I'm going to do Hello new
hit Enter.
So like yes
hitting. Why? And then I'll hit Control X to exit the text editor.
And now when I do cat Hello New.
We'll see that That's made the change for me. And then from there I could do a quick bash. Hello, new
and down There it is Hello world using that echo command. So that's awesome. Right
we know that we're route
we'll jump into the next command here. So I am route.
Let's say that I'm a different user or Europe in Tester Security test that you've gotten into a system. You want to know what permissions the user account hands? Well, you can use the command called I D,
and that gives you an output of the permissions that the account that you're currently logged into has. So that's a good, useful thing to have. Um, and then let's say you need to install something so you notice. Okay, I'm the route user. I can install new programs applications,
but how much space do I have? How much information can I really start on this drive right now? So D F
will show us the free disk space or the disk space that's free on the system and where everything's at, and it gives you this nice layout here of what's been used on the right when it's mounted on as far as the share would have you available space use space, et cetera, And so
that's a quick and easy way to do some troubleshooting or check to see how much free space you have.
I'm going to introduce you to what I think is one of the most important commands which is past W D, which is password for short.
And when we get in er
and asked me for a new password. So I'm gonna go ahead and update that
Oops. Looks like we made a mistake when we can't see what we're doing right? But that's okay. If I had done that correctly, what it would have done is updated my password. And that's very much important when you inherit a system. When you work on a system day to day and you know, maybe you need to change the password or something of that nature or
you don't want the default credentials on something,
then in a limits environment, you can use that past W D command, and it will allow you to change the password.
So I know that was a lot of information, but those were the commands that we want to start with and the things that we want to learn to use. Those were going to be fundamental and helping you to not only and it files and produce, you know, better scripts and things of that nature, but they're going to give you that foundational tool set to continue to move deeper and deeper
into your understanding of not just Callie
but Lennox platforms as a whole. So now that we've gone through that together, let's do a quick check on learning which command describes and shows you how to use other commands.
Now, thinking about that,
remember D F is going to show us disk space that free So DF down here. Nana was our text editor. So that's going to allow me to edit files and it content make scripts do things of that nature Cat allowed me to pull the output out of a filing displayed in the terminal like we did
cat Hello, new or cat? Hello. And that showed us all of the content of the foul.
So the last choice that we have here is man, which is short for manual. That shows us what a command does a description of the command and gives us a lot of good information on what we can do with respect to different switches and things of that nature with those commands that we put after man. So in summary in this very brief lesson today
we discussed the following the man command, the cat command echo. Nah, no, I d
DF and password or P past a B D for short, all of those air. Important because man is giving us instructions on how to use commands. Cat gives us outputs. If we don't want to open the file or looking, a text editor echoes going to allow us to do some things like
write scripts, display information, output information. So it's a great commander having your tool
chest. Nana was great for editing text files, but it's not the only text editor out there. Ideas great for understanding permissions. DF is good for understanding disk space utilization and where we might be able to clean some things up and passed. A beauty is fundamental and ensuring
that we change our password or that we don't use default credentials on the system.
So I know that that was brief, but I enjoyed having you here today, and I look forward to seeing you again soon.
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