sulogin - single-user login
is invoked by init
when the system goes into single-user
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
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
getpwnam(3) fails, then examine /etc/passwd and
/etc/shadow 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 sulogin will start a root shell without asking
for a password.
- Only use the -e option if you are sure the console is physically
protected against unauthorized access.
- -p, --login-shell
- Specifying this option causes sulogin 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,
sulogin will wait forever.
- -h, --help
- Display help text and exit.
- -V, --version
- Display version information and exit.
looks for the environment variable SUSHELL
to determine what shell to start. If the environment variable
is not set, it will try to execute root's shell from /etc/passwd
that fails, it will fall back to /bin/sh
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