Section: System Administration (8)
Updated: July 2014
sulogin - single-user login
is invoked by
when the system goes into single-user mode.
The user is prompted:
Give root password for system maintenance
(or type Control-D for normal startup):
If the root account is locked and --force is specified, no password is required.
will be connected to the current terminal, or to the optional tty device that
can be specified on the command line (typically
When the user exits from the single-user shell, or presses control-D at the
prompt, the system will continue to boot.
- -e, --force
If the default method of obtaining the root password from the system via
fails, then examine
to get the password. If these files are damaged or nonexistent, or when
root account is locked by '!' or '*' at the begin of the password then
will start a root shell without asking for a password.
Only use the
option if you are sure the console is physically protected against
- -p, --login-shell
Specifying this option causes
to start the shell process as a login shell.
- -t, --timeout seconds
Specify the maximum amount of time to wait for user input. By default,
will wait forever.
- -h, --help
Display help text and exit.
- -V, --version
Display version information and exit.
looks for the environment variable
to determine what shell to start. If the environment variable is not set, it
will try to execute root's shell from
If that fails, it
will fall back to
was written by Miquel van Smoorenburg for sysvinit and later ported
to util-linux by Dave Reisner and Karel Zak.
The sulogin command is part of the util-linux package and is available from
Linux Kernel Archive