“Single User” is a boot mode, you actually tells the unix shell that the OS should load only prompt (no GUI), and the local console login is the only login available (can’t be logged on from the network). Now the question is why we need to boot in Single User mode and the answer is, sometimes the system requires an administrative actions by the administrator, such as disk checkup, partition altering, drivers uninstalling, backups, etc.at this delicate tasks you don’t want other users to touch/create/remove/use files, hardware, CPU, and use …