Single User Mode What is Singe-user-mode and how can I boot in it?
Single-user mode is useful when something goes really wrong, e.g. the system is not able to boot properly or our biometric login does not work at all.
When you boot into this mode, you get
command line interface (bash).
Be careful, because you get root privileges and you can break the system even more easily if you are not sure what you do.
Also note that after booting into single-user mode, the root filesystem is mounted read-only, so you cannot modify any configuration files etc. You can switch the filesystem to read-write mode with command
mount -uw / (need to be done first). If previously the filesystem was not unmounted properly (e.g. the system froze before the restart), it can output an error. In that case you have to check the filesystem with
fsck utility (see "man fsck"). This utility should check the filesystem and (if possible) fix it and mark it as OK, so you can try
mount -uw / after the check.
After you are done, you can reboot (
reboot) or shutdown (
shutdown -h now).
How to boot in Single-user-mode?
You can trigger some options by pressing certain keys, or combination of keys on your keyboard during the boot.
To choose partiton to boot from (if you have multiple bootable partitions),
press Alt during the boot.
To force booting from CD/DVD,
press key C during the boot.
To start in single-user mode, press
Apple+S during the boot.
These options can be combined to some degree if it has some sense. For example if you have dual boot, you can use Alt; to choose the booting partition and then use
Apple+S when double-clicking on the icon of the right partition in the menu to boot into single-user mode.
Created on 12/6/2011 2:50:48 AM