Change the Root Password in Linux

To change the root password in Linux, you’ll need to run the “passwd” command from a root-level command prompt. If you know the current root password, you can use “su” to access the root account and run “passwd” right from a terminal window. If you’ve forgotten the root password, however, you’ll need to boot into single-user mode first, in order to get permission to run “passwd.” Learn how to change the Linux root password from the command line when booted normally or in single-user mode.

Steps

With the Current Root Password

  1. Press Ctrl+Alt+T to open a terminal window.[1] As long as you know the current root password, you can change it right from the desktop. This keyboard shortcut will open a new terminal window with a command prompt in all Linux desktop environments.
    • If you don’t have the current root password, see this method.
    • If you’re not using a desktop environment, you’re already at a command prompt, so just continue to the next step.
  2. Type su at the command prompt, then hit ↵ Enter.[2] A new line will open beneath the command prompt that says “Password:”
  3. Type the current root password, then press ↵ Enter. When the password is accepted, you’ll be brought back to the command prompt as the root user.
    • If you type the password incorrectly, just run su again and retry.
    • Passwords are case-sensitive.
  4. Type passwd, then press ↵ Enter. A new line will open beneath the command that says, “Enter new UNIX password:”
  5. Type a new password, then press ↵ Enter. The password you type will not appear on the screen, but you’ll be prompted to type it a second time to confirm.
  6. Retype the new password, then press ↵ Enter. You will see a message that says “password updated successfully.”
  7. Type exit and then press ↵ Enter. This will log you out of the root account.

Without the Current Root Password

  1. Start the computer and press the E key at the Grub menu.[3] This method will work for most popular Linux distributions (Ubuntu, CentOS 7, Debian).If you’ve lost the root password, you can reset it in single-user mode. The Grub menu appears right after you turn on the computer. In most cases, it only stays on the screen for a few moments.
    • If you don’t press E before the Grub menu disappears, reboot and try again.
    • There are many distributions of Linux, some more obscure than others. If you’re not able to get to single-user mode with this method, check your distribution’s website for instructions specific to your system.
  2. Use the ↑ ↓ keys to scroll to the line that begins with “linux /boot”. This is the line you’ll need to modify in order to boot into single-user mode.
    • In CentOS and some other distributions, the line may begin with “linux16” instead of just “linux.”
  3. Use the → ← ↑ ↓ keys to move the cursor to the end of the line. The line ends with ro, so place the cursor right after that.
  4. Type init=/bin/bash at the end of the line. The end of the line should now look like this: ro init=/bin/bash.
    • Note the space between ro and init=/bin/bash.
  5. Press Ctrl+X to boot into single-user mode. This will tell the system to boot directly to a root-level command prompt.
  6. Type mount –o remount,rw / at the prompt, then press ↵ Enter. This mounts the file system in read-write mode.
  7. Type passwd at the prompt, then press ↵ Enter. Since booting into single-user mode gives you root access, there’s no need to pass additional parameters to the “passwd” command.
  8. Type a new password for the root user, then press ↵ Enter. Note that you won’t see the characters you type on the screen. This is normal.
  9. Type the new password again when prompted, then press ↵ Enter. When the system confirms you’ve re-entered the same password, you’ll see a message that says “password updated successfully.”
  10. Type reboot –f and then press ↵ Enter. This command reboots the system normally.

Tips

  • Make sure your passwords are 8 characters or more and contain a mix of letters (upper and lowercase), numbers and symbols.
  • To change the password for another user, "su" to root and type "passwd <username>".

Related Articles

Sources and Citations

  1. ↑ https://help.ubuntu.com/community/UsingTheTerminal
  2. ↑ http://www.tldp.org/LDP/lame/LAME/linux-admin-made-easy/changing-user-passwords.html
  3. ↑ http://www.unixmen.com/linux-basics-reset-forgotten-password-ubuntu/
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