One of the advantages of single-user mode is that you do not need a boot CD-ROM; however, it does not give you the option to mount the file systems as read-only or not mount them at all.
If your system boots, but does not allow you to log in when it has completed booting, try single-user mode.
In single-user mode, your computer boots to runlevel 1. Your local file systems are mounted, but your network is not activated. You have a usable system maintenance shell. Unlike rescue mode, single-user mode automatically tries to mount your file system. Do not use single-user mode if your file system cannot be mounted successfully. You cannot use single-user mode if the runlevel 1 configuration on your system is corrupted.
On a Linux system using GRUB, use the following steps to boot into single-user mode:
- At the GRUB splash screen at boot time, press any key to enter the GRUB interactive menu.
- Select the installed Linux O/S with the version of the kernel that you wish to boot and type a to append the line.
- Go to the end of the line and type single as a separate word (press the Spacebar and then type single). Press Enter to exit edit mode.