SULOGIN(8)

NAME
sulogin - Single-user login

SYNTAX
sulogin [ tty-device ]

DESCRIPTION
sulogin is invoked by /etc/init prior to allowing the user access to the system when in single user mode. This feature may only be available on certain systems where init has been modified accordingly, or where the /etc/inittab has an entry for a single user login.

The user is prompted

    Type control-d for normal startup,
    (or give root password for system maintenance):

Input and output will be performed with the standard file descriptors unless the optional device name argument is provided.

If the user enters the correct root password, a login session is initiated. When EOF is pressed instead, the system enters multi-user mode.

After the user exits the single-user shell, or presses EOF, the system begins the initialization process required to enter multi-user mode.

CAVEATS

This command can only be used if init has been modified to call /etc/sulogin instead of /bin/sh, or if the user has set the inittab to support a single user login. For example, the line

co:s:respawn:/etc/sulogin /dev/console

should execute the sulogin command in single user mode.

As complete an environment as possible is created. However, various devices may be unmounted or uninitialized and many of the user commands may be unavailable or nonfunctional as a result.

Files
/etc/passwd - user account information
/etc/shadow - encrypted passwords and age information
/.profile - initialization script for single user shell

See Also
login(1), init(1M), sh(1)