In Red hat Linux; this is called the last option for troubleshooting. The system will be booted first by the bootable cd or floppy of Linux. When the Linux installation screen will come, there is a command prompt. Give the command as below,
boot ] linux rescue
ð After installation of keyboard, mouse, the language etc, again there will be another command prompt or single user mode, execute command as below,
boot ] chroot /mnt/sysimage
ð Now we have the ability to troubleshoot.