CentOS Linux OS

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Last Updated: Thursday, 30 December 2021 15:44

Published: Wednesday, 12 February 2020 04:39

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CentOS:

This is the second best OS after Linux Mint (for a newbie to Linux). It's interface is clean, and is a no frills OS. It's supported by RedHat, so it has same level of stability for OS that is expected of any large company. Best part is that it has lots of help available online. CentOS is my first choice of any Linux OS, It's screen doesn't look similar to windows, but otherwise it's very simple to use even for a person new to Linux. it's up on my laptop 24/7 for more than a year with no crashes !!

Versions:

There are many versions of CentOS Linux, as CentOS-6, CentOS-7 and CentOS-8 (as of Oct, 2021). CentOS 7 is very widely used, so I would advise to stick with CentOS 7. CentOS 8 is not going to be supported for long, so don't bother with CentOS 8. CentOs-8 is going to be followed by CentOS Stream, which is a new direction for CentOS. Until now, CentOS Linux were a rebuild of RHEL (Red Hat enterprise Linux), and so were called "downstream release" of RHEL. Starting with CentOS stream, it's going to be the other way round, where RHEL is going to be a downstream build of CentOS stream. So, your CentOS stream for laptop will be available with all latest/greatest features of RHEL, even before enterprise consumers see it.

However, for our purpose, CentOS 7 is going to suffiice for next 5 years without any issues, so we'll talk about stream in 2026.

Installating OS:

Download, install using these links:

https://www.tecmint.com/centos-7-installation/33333

steps:

1. Download CentOS ISO:

https://www.centos.org/download/

Download x86-64 bit as that's what almost all laptops using Intel/AMD chips are going to need.

2. Copy ISO files to USB drive:

You need linux already installed in order to cp the iso to usb from within linux. We don't use UUI to burn the iso as explained previously (it doesn't work anyway), so "cp" is the only way to get CentOS installed. So, in order to get CentOS installed, you need an already installed linux distro on some other laptop. Use cp cmd as explained under installation.

1A. Use cp cmd to copy to usb drive

sudo cp /home/aarav/Downloads/CentOS-7-x86_64-Everything-1804.iso /dev/sdb => Do not use /dev/sdb1. See in "Linux Installation section for details"

1B. Do NOT use dd to copy.

Follow instructions from above for running dd. run "lsblk" to get device name for usb. Run dd.

sudo dd if=/home/aarav/Downloads/CentOS-7-x86_64-Everything-1804.iso of=/dev/sdb status=progress oflag=sync

3. Reboot Windows:

Once copied, plug it in windows laptop and reboot it. Do not use UUI, as it gives error. You will be greeted with "Install centos-7" screen. Follow prompts as explained in link above from tecmint.

Once CentOS is installed, you have to reboot your computer once again. Now you will be greeted with "GRUB" bootloaded which will ask you to choose the OS you want to login with. One issue that I've seen with CentOS is that the grub boot menu may not have "windows boot" option in it at all. To fix this, do this:

1. log into centos linux, open a terminal and type these 2 cmds: ( https://bytefreaks.net/gnulinux/ntfs-support-on-centos-7 )
2. sudo yum --enablerepo=extras install epel-release
3. sudo yum install ntfs-3g -y
4. https://unix.stackexchange.com/questions/169787/windows-boot-option-is-missing-after-installing-centos-7-how-can-i-get-it-back .
   1.  type this cmd: sudo grub2-mkconfig > /dev/null => This will show windows 10 loader on /dev/sda1. Now run below 2 cmds:
      • sudo cp /boot/grub2/grub.cfg /boot/grub2/grub.cfg.old
      • sudo grub2-mkconfig -o /boot/grub2/grub.cfg
5. This will allow us to boot into windows

Few more helpful links:

https://wiki.centos.org/HowTos/InstallFromUSBkey

https://www.centos.org/forums/viewtopic.php?t=56144 => This not relevant as it's for UUI

Install desktop environment (DE):

Read about DE on "linux installation" to get some background. Here's a way to install different DE on CentOS. You may not need to do any of this if you are already satisfied with the default DE that is installed on your CentOS version.

sudo yum grouplist => lists all groups. It lists various DE as Cinnamon Desktop, MATE Desktop, Xfce, KDE Plasma Workspaces, GNOME Desktop, etc

sudo yum groupinfo "Cinnamon Desktop" => provides more info about this DE pkg. Do this for any pkg before installing it to make sure you installing what you think you want to install.

sudo yum groupinstall "Cinnamon Desktop" => this is cinnamon de used in Linux Mint.

sudo yum groupinstall "MATE Desktop" => this is continuation of GNOME2, which was much more liked. This is the default on CentOS 6.

sudo yum groupinstall "GNOME desktop" => This is GNOME3 DE, which is a big departure from GNOME2 and not liked by everyone. However, it's the default on CentOS 7. gnome classic and gnome shell are the 2 gnome de available here.

sudo yum groupinstall "KDE Plasma Workspaces" => This is the old conventional KDE desktop

sudo yum groupinstall Xfce => This is Xfce desktop. very light weight.

To remove a DE, we can do:

sudo yum groupremove "MATE Desktop" => uninstalls and removes all MATE DE related files.

Installing other software:

Here are links for few more pgms to install. Firefox and Skype are the important ones. Luckily they install flawlessly.

Install Firefox browser:

Firefox is installed by default. If not installed, type these cmds on Terminal.

firefox -version => shows version of firefox installed. If it's not installed or not latest one, run below cmds

sudo yum install firefox => installs firefox when nothing was installed.

sudo yum update firefox => This updates firefox to latest version if it was already installed.

firefox -version => Now check if it shows the latest version.

Install Skype:

Installing skype is very easy on CentOS. Type the 2 below cmds on terminal.

wget https://repo.skype.com/latest/skypeforlinux-64.rpm

sudo yum localinstall skypeforlinux-64.rpm

Now launch skype on clicking on Skype icon, or type "skypeforlinux" on terminal.

Issues and Solutions:

Sometimes some of the graphic applets will crash and not appear any more when you restart your system. As an example, the battery charge indicator icon (on the top right corner) may disappear. You just have to restart that applet, by finding out the exact name of the applet.

Network Manager applet crash: If your network manager applet (the one that shows the internet connection with bars) disappears, these are the steps to restore it. On the terminal, type the below cmds:

• $ which nm-applet => returns something like this: /usr/bin/nm-applet
• $ nm-applet => now run the applet. Doesn't show any o/p.
• $ service NetworkManager restart => Now restart nm. It shows msg as below:
  • Redirecting to /bin/systemctl restart NetworkManager.service

This will restore the network manager applet back.