Change root Password Centos single user mode

CentOS Single User Mode is a specialized boot mode that provides limited functionality, primarily used for maintenance and administrative tasks. This mode allows system administrators to perform critical operations such as troubleshooting, repairing file systems, or changing passwords without the interference of other users or services. Single User Mode runs as a single user (root) environment without network capabilities, offering a secure setting for essential system repairs.

Booting CentOS into Single User Mode

Booting CentOS into Single User Mode involves a few key steps to ensure safe and controlled access to this maintenance environment. This mode is essential for performing system-level changes without interference from running services or users.

Step 1: Restart Your CentOS System

To begin the process, restart your CentOS system. This can be done from the terminal using the reboot command or by selecting the restart option through the system’s interface. Ensure that you have administrative privileges to perform this action.

Step 2: Access the GRUB Menu

During the boot sequence, quickly press the Esc key (or Shift key for some systems) to access the GRUB menu. The GRUB menu is the boot loader interface where you can modify boot settings and select different boot modes.

Step 3: Modify Boot Parameters

Once in the GRUB menu, highlight the CentOS entry and press e to edit the boot parameters. Navigate to the line starting with linux or linux16 and append rd.break or single at the end of the line. This modification tells the system to boot into Single User Mode.

Changing the Root Password

To change the root password in Single User Mode, follow these steps to ensure a secure update of your system’s credentials.

Using the ‘passwd‘ Command

Once the system has booted into Single User Mode and you have gained access to the root shell, remount the system in read-write mode to allow changes:

mount -o remount,rw /

After remounting, use the passwd command to change the root password:

passwd

Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully