Understanding Linux File Permissions and Ownerships

From one of our previous articles "How to manage Linux Users and Groups" we discussed on how Linux becomes a multi-user OS, what is a user and a group with their configurations. By design, even though Linux allows multiple users can use the same computer in the same time without affecting others, Linux doesn't allow you to access or modify files belonging to other users. If Linux allows you to do it, that would be a security risk. But somehow they have implemented a security measure to mitigate that security risk. With that we can make sure only desired users and groups can access the relevant files and directories.

If we take a small demonstration. Here, we will log in as a normal user and try to access a root directory.

It gave a permission denied error when accessing. Why ? That's because /root directory is owned by user root. Only a privileged user can access or modify that.

So, Linux introduces two kind of factors which tells who can access or modify a file as w…

How to install Linux in VMware workstation

There are so many distribution of Linux operating system, like Red Hat Linux, CentOS, Fedora, Ubuntu, Debian, Mint, Kali Linux and so many types. All most all of these distributions are similar, but some different in areas like when installing packages ( packages like softwares in windows) and when working with services. That's just a basic idea. Not like in windows, when using Linux we need to deal with commands all the time, simply need to work writing codes for every task. But it's easy :)

We will learn how to install and configure Linux in a VMware workstation. So, i am using CentOS distribution and VMware workstation 15 for my work. You can download CentOS 7 and VMware workstation 15 from the Internet.
Installation in VMware workstation can be done in two ways. Typical and custom. We will the first way here.
Recommendation : Your PC should have a RAM of at least 2GB.

Open VMware workstation 15 and follow the below steps.

Go to,
File > New Virtual Machine

1. Using typical settings.

1.1) Click the post installation. So we can install the operating system after creating the virtual machine. Or if you want to select the image file of the operating system, you can set it here as well from the second option. If you use a Disk (CD or DVD) use the first option.

1.2) Select the Guest Operating system as Linux. This OS that we install becomes a guest OS as we are installing it on a virtual machine where VMware workstation (hypervisor  we use here) is installed on a computer which already has installed a OS.

1.3) Give a name for the Virtual machine in the first box, here i am giving the name as CentOS-client and give a place where the virtual machine should be saved.

1.4)  Here i use a CentOS minimal iso file which means it has command line interface. The minimum disk requirement for a minimal OS is 8GB in linux. Select Split virtual disk into multiple files as it stores files part by part, not a single file. No matter you can use whatever distribution of linux and can give 20GB for your disk size.

1.5) Here is the end of the installation of the virtual machine. Now we need to install the operating system into the virtual machine.

Overview after installing your virtual machine in your VMware workstation.

1.6) Now we will select the ISO image file of CentOS. Click on CD/DVD as below image.

1.7) Go to Use ISO image file and give your CentOS-7 ISO file. Press OK and power up the Virtual machine.

* VM is starting up.

1.8) Select Install CentOS 7

1.9) Select the language as English.

How to install Cent OS-7 in VMware workstation.

2.0) In System, if it was red - go inside and select the drive.

2.1) For Network & Host name, Enable the Ethernet ( default is off )

2.2) Press the Done and Click Begin Installation on the bottom. Then you will get a window for creating a root password and to create a user and give a password for that user. I will explain who is a root user in Linux with another article.

It will take some time for the installation. 
After the installation, it will ask for a reboot of Virtual machine. Then do it. Below is the login screen. So you can give your created username of the new account. I created the account with the name student and password as student. So you can give your username and password.

Now you have installed and configured a virtual machine with CentOS-7 installed.

VMware workstation 15 download link : https://www.vmware.com/products/workstation-pro/workstation-pro-evaluation.html

Congratulations!. Keep it up. Cheers.


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