Reset root password on CentOS / RHEL

First, try single user. If you don’t see either a LILO or GRUB boot screen, try hitting CTRL-X to get one. If it’s LILO, just type “linux single” and that should do it (assuming that “linux” is the lilo label). If GRUB, hit ‘e”, then select the “kernel” line, hit “e” again, and add ” single” (or just ” 1″) to the end of the line. Press ENTER, and then “b” to boot.

You should get a fairly normal looking boot sequence except that it terminates a little early at a bash prompt. If you get a “Give root password for system maintenance”, this isn’t going to work, so see the “init” version below.

If you do get the prompt, the / filesystem may not be mounted rw (although “mount” may say it is). Do

mount -o remount,rw /

If that doesn’t work (it might not), just type “mount” to find out where “/” is mounted. Let’s say it is on /dev/sda2. You’d then type:

mount -o remount,rw /dev/sda2

If you can do this, just type “passwd” once you are in and change it to whatever you like.