RHEL 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 how to list groups in Linux and check user group membership using commands like groups, id, getent, compgen, and /etc/group. This guide explains how to view all groups, list groups for a user, and display users …

Step by Step instructions to install yarn on Linux and WIndows. Installation on Ubuntu (Debian based) and Rocky Linux (Red hat based) and Windows.

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.

How to extract/unpack/uncompress the contents of the initramfs image on RHEL7 and RHEL8? How do I list initramfs image file content? How do I modify the contents of an initrd or initramfs? How do I view an initrd or …

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 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 mount a USB drive in Linux using command line tools. This step-by-step guide explains how to identify USB devices, install required filesystem packages, mount USB drives manually, verify mount points, …

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

An overview on systemd-journald service, how logging happens in RHEL 7 Linux with Journals and systemd-journald logrotate. Compare systemd-journald vs rsyslogd

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?