Getting into Single User Mode in CentOS 5

Unlike FreeBSD, which lets you boot into single user mode from a startup menu, getting into Single User Mode in CentOS is a little more complicated. Here's how:

• Reboot the system:

  bash# reboot

• When the system reboots, it will say 'Press any key to enter the boot menu….'. Press a key, and you'll get to GNU GRUB.
• Choose the kernel you want (probably the one that's listed on top), and press e
• Scroll down to the partition that has your kernel on it (it should start with kernel) and press e again.
• It will now display something like:

  <0/LogVol00

  Enter <space> single after that, so you've got:

  <0/LogVol00 single

  That tells CentOS to boot at run-level 1 in single user mode. You can also type emergency instead of single, which does the same thing but doesn't start any of your init scripts.

• Hit return to get back to the screen that lists your kernel, and then hit b to boot.

More info on single user mode and rescue mode is available from the CentOS docs.