| .\" Copyright (C) 1998-2006 Miquel van Smoorenburg. |
| .\" Copyright (C) 2012 Karel Zak <kzak@redhat.com> |
| .\" |
| .\" This program is free software; you can redistribute it and/or modify |
| .\" it under the terms of the GNU General Public License as published by |
| .\" the Free Software Foundation; either version 2 of the License, or |
| .\" (at your option) any later version. |
| .\" |
| .\" This program is distributed in the hope that it will be useful, |
| .\" but WITHOUT ANY WARRANTY; without even the implied warranty of |
| .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| .\" GNU General Public License for more details. |
| .\" |
| .\" You should have received a copy of the GNU General Public License |
| .\" along with this program; if not, write to the Free Software |
| .\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| .\" |
| .TH SULOGIN "8" "July 2014" "util-linux" "System Administration" |
| .SH NAME |
| sulogin \- single-user login |
| .SH SYNOPSIS |
| .BR sulogin " [options]" |
| .RI [ tty ] |
| .SH DESCRIPTION |
| .B sulogin |
| is invoked by |
| .B init |
| 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 |
| .B sulogin |
| will be connected to the current terminal, or to the optional \fItty\fR device that |
| can be specified on the command line (typically |
| .BR /dev/console ). |
| .PP |
| When the user exits from the single-user shell, or presses control\-D at the |
| prompt, the system will continue to boot. |
| .SH OPTIONS |
| .IP "\fB\-e\fR, \fB\-\-force\fP" |
| If the default method of obtaining the root password from the system via |
| .BR getpwnam (3) |
| fails, then examine |
| .I /etc/passwd |
| and |
| .I /etc/shadow |
| to get the password. If these files are damaged or nonexistent, |
| .B sulogin |
| will start a root shell without asking for a password. |
| .IP |
| Only use the |
| .B \-e |
| option if you are sure the console is physically protected against |
| unauthorized access. |
| .IP "\fB\-p\fR, \fB\-\-login\-shell\fP" |
| Specifying this option causes |
| .B sulogin |
| to start the shell process as a login shell. |
| .IP "\fB\-t\fR, \fB\-\-timeout \fIseconds\fP" |
| Specify the maximum amount of time to wait for user input. By default, |
| .B sulogin |
| will wait forever. |
| .IP "\fB\-h\fR, \fB\-\-help\fP" |
| Display help text and exit. |
| .IP "\fB\-V\fR, \fB\-\-version\fP" |
| Display version information and exit. |
| .SH ENVIRONMENT VARIABLES |
| .B sulogin |
| looks for the environment variable |
| .B SUSHELL |
| or |
| .B sushell |
| to determine what shell to start. If the environment variable is not set, it |
| will try to execute root's shell from |
| .IR /etc/passwd . |
| If that fails, it |
| will fall back to |
| .IR /bin/sh . |
| .SH AUTHOR |
| .B sulogin |
| was written by Miquel van Smoorenburg for sysvinit and later ported |
| to util-linux by Dave Reisner and Karel Zak. |
| .SH AVAILABILITY |
| The sulogin command is part of the util-linux package and is available from |
| .UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/ |
| Linux Kernel Archive |
| .UE . |
