===== Reset Root Password =====
==== On CentOS & RHEL ====

1. Reboot and Access GRUB Menu
  * Reboot the system.
  * During boot, when GRUB appears, press **e** to edit the default kernel entry.

2. Edit the Kernel Boot Parameters
  * Find the line beginning with linux16
  * Replace:

  ro

  * with:

  rw init=/sysroot/bin/sh

3. Boot with Modified Parameters

  * Press Ctrl + X to boot into single-user mode.

4. Access the System

  * Once booted, you'll be at a prompt. Run:

  chroot /sysroot

5. Reset Password

  * Enter:

  passwd root

  * Set the new password.

6. Relabel SELinux Contexts (if enabled)

  * If SELinux is enforcing, run:

  touch /.autorelabel

7. Exit and Reboot

  * Run:

  exit
  reboot

==== On Ubuntu ====

1. Reboot and Access GRUB Menu

  * Reboot the system.
  * When GRUB menu appears, select the entry you want to modify and press e.

2. Edit the Boot Parameters

  * Look for the line that starts with:

  linux


  * Replace:

  ro quiet splash

  * or similar with:

  rw init=/bin/bash

3. Boot into Shell

  * Press Ctrl + X or F10 to boot.

4. Reset Password

  * At the root shell prompt (#), enter:

  passwd root

  * Enter a new password when asked.

5. Remount and Reboot Cleanly

  * Ensure the root filesystem is mounted correctly:

  mount -o remount,rw /

  * Then reboot:

  exec /sbin/init

  * or

  reboot -f