1SULOGIN(8) System Administration SULOGIN(8)
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6 sulogin - single-user login
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9 sulogin [options] [tty]
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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 (or type Control-D for normal
17 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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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 without
36 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 as
43 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 Print version and exit.
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56 sulogin looks for the environment variable SUSHELL or sushell to
57 determine what shell to start. If the environment variable is not set,
58 it 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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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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66 For bug reports, use the issue tracker at
67 https://github.com/util-linux/util-linux/issues.
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70 The sulogin command is part of the util-linux package which can be
71 downloaded from Linux Kernel Archive
72 <https://www.kernel.org/pub/linux/utils/util-linux/>.
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76util-linux 2.38 2022-02-17 SULOGIN(8)