1SULOGIN(8)                   System Administration                  SULOGIN(8)
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NAME

6       sulogin - single-user login
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SYNOPSIS

9       sulogin [options] [tty]
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DESCRIPTION

12       sulogin is invoked by init when the system goes into single-user mode.
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14       The user is prompted:
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16            Give root password for system maintenance
17            (or type Control-D for normal startup):
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19       If  the root account is locked and --force is specified, no password is
20       required.
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22       sulogin will be connected to the current terminal, or to  the  optional
23       tty  device  that  can  be  specified  on  the  command line (typically
24       /dev/console).
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26       When the user exits from the single-user shell, or presses control-D at
27       the prompt, the system will continue to boot.
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OPTIONS

30       -e, --force
31              If  the  default  method of obtaining the root password from the
32              system via  getpwnam(3)  fails,  then  examine  /etc/passwd  and
33              /etc/shadow  to get the password.  If these files are damaged or
34              nonexistent, or when root account is locked by '!' or '*' at the
35              begin of the password then sulogin will start a root shell with‐
36              out asking for a password.
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38              Only use the -e option if you are sure the console is physically
39              protected against unauthorized access.
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41       -p, --login-shell
42              Specifying this option causes sulogin to start the shell process
43              as a login shell.
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45       -t, --timeout seconds
46              Specify the maximum amount of time to wait for user  input.   By
47              default, sulogin will wait forever.
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49       -h, --help
50              Display help text and exit.
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52       -V, --version
53              Display version information and exit.
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ENVIRONMENT VARIABLES

56       sulogin looks for the environment variable SUSHELL or sushell to deter‐
57       mine what shell to start.  If the environment variable is not  set,  it
58       will  try  to execute root's shell from /etc/passwd.  If that fails, it
59       will fall back to /bin/sh.
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AUTHOR

62       sulogin was written by Miquel van Smoorenburg for  sysvinit  and  later
63       ported to util-linux by Dave Reisner and Karel Zak.
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AVAILABILITY

66       The  sulogin command is part of the util-linux package and is available
67       from Linux Kernel Archive ⟨https://www.kernel.org/pub/linux/utils/util-
68       linux/⟩.
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72util-linux                         July 2014                        SULOGIN(8)