path: root/login-utils/sulogin.8

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.TH SULOGIN 8 "28 Feb 2012" "" "Linux System Administrator's Manual"
.SH NAME
sulogin \- Single-user login
.SH SYNOPSIS
.B sulogin
.RB [ options ]
.RB [ tty ]
.SH DESCRIPTION
.I sulogin
is invoked by \fBinit\fP when the system goes into single user mode.
.PP
The user is prompted:
.IP "" .5i
Give root password for system maintenance
.br
(or type Control\-D for normal startup):
.PP
\fIsulogin\fP will be connected to the current terminal, or to the
optional tty device that can be specified on the command line
(typically \fB/dev/console\fP).
.PP
After the user exits the single-user shell or presses control\-D at the
prompt, the system will continue to boot.
.SH OPTIONS
.IP "\fB\-e, \-\-force\fP"
If the default method of obtaining the root password via \fBgetpwnam\fP(3) from
the system fails, manually examine /etc/passwd and /etc/shadow to get the
password. If they are damaged or nonexistent, sulogin will start a root shell
without asking for a password.

Only use the \fB\-e\fP option if you are sure the console is physically
protected against unauthorized access.
.IP "\fB\-h, \-\-help\fP"
Print a help message.
.IP "\fB\-p, \-\-login\-shell\fP"
Specifying this option causes sulogin to start the shell process as a
login shell.
.IP "\fB\-t, \-\-timeout \fIseconds\fP"
Specify the maximum amount of time to wait for user input. By default,
sulogin will wait forever.
.IP "\fB\-V, \-\-version\fP"
Output version.
.SH ENVIRONMENT VARIABLES
\fIsulogin\fP looks for the environment variable \fBSUSHELL\fP or
\fBsushell\fP to determine what shell to start. If the environment variable
is not set, it will try to execute root's shell from /etc/passwd. If that
fails it will fall back to \fB/bin/sh\fP.
.SH AUTHOR
Miquel van Smoorenburg <miquels@cistron.nl>