CentOS tutorials

Compare AlmaLinux 9/10 and Rocky Linux 9/10 for servers: RHEL compatibility models, support timelines, cPanel support, migration tools, hardware requirements, patching philosophy, and when to pick each Enterprise Linux …

Compare AlmaLinux 9 and 10 with Ubuntu 24.04 LTS for servers: RHEL compatibility, dnf vs apt, SELinux vs AppArmor, support timelines, cPanel hosting, cloud images, migration from CentOS, and practical workload guidance.

Learn how to force Chrony time sync in Linux using chronyc makestep and chronyd -q. Also configure Chrony as an NTP client or server, check sync status, and understand server options like iburst, minpoll, and maxpoll.

Step-by-Step instructions to disable transparent hugepages GRUB2 using grub2-editenv in RHEL/CentOS 8 Linux. Check transparent huge pages status (AnonHugePages)

Step-by-Step Tutorial to configure hugepages in red hat and centos 7/8 linux using vm nr_hugepages in /etc/sysctl.conf. Also configure hugepages pool using hugeadm

Learn how to check if CPU supports HugePages with 2MB and 1GB Size in CentOS/RHEl 7 Linux and change default hugepage size permanently using GRUB2 with examples

What are transparent huge pages? How to check turn off disable transparent hugepages in RHEL / CentOS 7 Linux for this session or permanently sysctl GRUB2?

Learn how to check sudo access in Linux. Check if you or another user has sudo privileges with sudo -l, test sudo access non-interactively in a bash script with sudo -n, and list all sudo users, with real tested output.

Learn how to add a Linux user to the sudo group on Ubuntu and Debian, use the wheel group on RHEL-based systems, verify sudo access, and avoid confusing group-based sudo with custom sudoers file rules.

Learn how to check Linux kernel version with tested uname, hostnamectl, procfs, journalctl, dmesg, boot image, dpkg, and apt commands, and understand the difference between the running kernel and installed kernel …

Learn when and how to restart crontab in Linux. See cron restart and reload commands for Ubuntu, Debian, RHEL, CentOS—and when a restart is NOT required.

To create custom ISO in RHEL/CentOS 8, create a kickstart file and modify the isolinux.cfg for boot menu. You can also minimze the package list and update repodata

Step by Step tutorial to configure samba active directory domain controller in CentOS 8 Linux. Install Windows AD alternative in Linux. Free domain controller software in Linux

Step by Step NFS configuration Guide to install and configure NFS server in RHEL/CentOS 7/8. NFS server tutorial. How to check NFS status in Linux. setup nfs server

Learn how to downgrade RPM packages in Linux using yum and rpm. This guide covers installing specific versions, handling dependencies, forcing downgrade, rollback using yum history, and fixing common errors in CentOS, …

Learn how to list users in Linux using commands like getent, /etc/passwd, compgen, who, and id. This guide explains multiple practical methods to view all users, logged-in users, normal users, system accounts, and users …

Step by step guide to add linux to windows Domain (Active Directory) using Realm tool on RHEL/CentOS 7/8. Join linux to windows domain. sssd active directory centos 7.

Steps to run script with systemd at shutdown only with examples in CentOS/RHEL 7/8 in Linux. Run script or command before shutdown but not at reboot

How to execute command or run script after N minutes of boot using systemd timer in CentOS/RHEL 7/8 Linux fix systemctl failing with unknown section 'Timer'

Shell script to read user input during boot stage in Linux with a systemd service in CentOS/RHEL 7/8 Linux. Take input at the startup script in Linux.

How to execute and run script at startup after N minutes with delay using systemd and without cronjob in CentOS/RHEL 7/8 Linux before login prompt appears

Steps to execute and run script with systemd right before shutdown in CentOS/RHEL 7/8 Linux. Use Before=shutdown.target to execute command before shutdown

How to execute or run script with systemd right before login prompt in CentOS/RHEL 7/8 Linux between rc-local.service and getty.target in service unit file

run service as user linux. systemd allow user to start service. systemd start service as user on boot run systemd service as specific user group CentOS/RHEl 7/8

We mount filesystem using /etc/fstab to make the changes persistent across reboot. Now there is another way to mount filesystem without fstab using systemd.

Steps to automount file system using systemd automount unit file without /etc/fstab to automatically mount and unmount file system in rhel/centos 7 and 8

Creating /forcefsck and /fsckoptions doesn't work on CentOS/RHEL 7/8 Linux How to perform force file system check on boot (next reboot) using systemd-fsck?

Perform rootkit malware scanner centos rhel linux using rkhunter. detect rootkit malware using rkhunter with examples. Analyse rkhunter logs

Step by Step guide to upgrade or migrate CentOS 7 and 8 to Rocky Linux 8. There will be no data loss during the migration.

The process of upgrading from CentOS 7 to CentOS 8 is not straightforward. There are significant differences between the two versions, including the