Hello, everyone, and welcome to this lesson.
In this lesson, we are going to understand a very important concept about network repositories and
Kali Linux.
Now what are repositories?
So it's basically a place from where you can fetch, download and install all the tools or softwares
that you want in your Linux machine.
Kali by default has its own repo that you can update and fetch tools or any programs that you want.
But sometimes there are some tools or other programs which are not in the official repository.
So to do that, you have to manually add new repositories in your operating system.
Once you add this new repo path, it allows you to fetch, download, and install those new tools or
programs.
So in this lesson, we are going to walk through that.
What are sources start list repositories?
How you can come across an error when you want to install a specific software which is not in the official
repo.
How to fix it by adding a new path in the source start list and update the repository of our Kali Linux
machine and then successfully install that software that you want.
So the first thing that we are going to see is we are going to read these sources start list file which
is inside Etsy apt.
When you go over here by default in the Linux default installation, this is the official repo that
you will see now when you navigate to the next directory which is sources dot list dot D, you can see
over here there are three list files which are been added explicitly which allows you to install Google
Chrome, protonvpn, sublime text dot list, etc..
Now let us try to read one of the list file.
So let's say we are reading Google Chrome dot list here.
You can see this file is automatically configured which is written in comment.
You may comment out this entry, but any of the modifications may be lost.
Here you can see the architecture is AMD 64.
The version of the program that is going to be downloaded is for Debian.
It is going to be downloaded from this specific URL, which is DL, which stands for download or Google.com
Linux Chrome for Debian, the stable main version.
I hope you guys understood this.
Now let us see the next one.
This one is for Protonvpn stable dot list.
It says that this is a Debian download.
This is a specific URL which has been signed by a keyring, which is a valid certificate which allows
to download files officially from the server.
Let us see the next one.
Let's see what's next.
So let's say I want to install this program, which is signal now signal like any other application
like Telegram or WhatsApp.
It allows you to do communication.
This specific software is not in the official repository, which means you cannot install it directly
by typing the command app to get install signal.
So once we go on this website here we see the Linux Debian based install instructions which we are going
to follow in which we primarily are going to give the repository path to our Linux machine and then
we are going to fetch the tool and install it successfully.
So here you can see there are three steps.
Step one, to install our official public software signing key, which will validate that the request
that is going is valid and you will be able to download the software.
Next is adding the repository to your list of repositories and finally the command to install this tool.
Let's see what happens if we directly run the command without giving the path to the repo.
In our source short list you can see our machine will give an error like this which says unable to locate
package, this is because it is unable to identify the signal desktop package into the official default
repository which it is trying to fetch from.
Okay.
So we are going to follow the steps one by one.
The first step is to give the official signing key in our system.
The next step is going to download the repository to our sources start list.
So I'm going to copy paste the command over here.
Here you can see this is exactly the same thing that we saw in Chrome and Protonvpn, which says the
architecture is aimed 64 for Debian assigning key and from there the program or the tool needs to be
downloaded from.
Let us verify this by going in the same directory.
And you can see over here signal dot list.
One more list has been created successfully and when we try to read this list it is exactly as same
as for Google Chrome and Protonvpn.
Great.
So now we have successfully added the list in our Kali Linux.
Now we need to update our repositories.
So for that we have to run the command, which is sudo apt update when we run this command.
It allows our Linux machine to update the repo path and fetch the tools from new given source to start
list.
As you can see get one request says that it has successfully updated its repo path to fetch programs
from update signal dot org.
Next we saw google.com.
The third one is update start signal dot org.
Again, these are all the custom path that we have added that we want to fetch the programs from the
next hit.
As you can see over here are basically the default rip apart from where it is trying to fetch, if there
has been new programs that has been added or any new packages that have been updated.
It will take few seconds to update its official repository and we just have to wait in for here.
Once this step is completed successfully, we would now be able to run the command, which is to install
the signal package.
As we saw before, when we ran that specific command, it gave us an error.
But let us see this time what will happen?
Will it again give an error or will it allow us to install?
So it's almost complete.
So we are going to base the command this time and hit enter and you can see it is successfully installing
the package that we want.
Here we can see previously we got the error while installing the signal text drop package.
We successfully ran the first command to add the list file in our system and the key ring as well.
After that we did an APT update and then we were successfully able to install the package in our system.
I hope you guys understood this.
Thank you.