xref: /netbsd-src/sbin/shutdown/shutdown.8 (revision ae9172d6cd9432a6a1a56760d86b32c57a66c39c)
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32.\"     from: @(#)shutdown.8	8.1 (Berkeley) 6/5/93
33.\"	$Id: shutdown.8,v 1.5 1994/09/17 00:10:11 mycroft Exp $
34.\"
35.Dd June 5, 1993
36.Dt SHUTDOWN 8
37.Os BSD 4
38.Sh NAME
39.Nm shutdown
40.Nd "close down the system at a given time"
41.Sh SYNOPSIS
42.Nm shutdown
43.Op Fl
44.Op Fl fhkrn
45.Ar time
46.Op Ar warning-message ...
47.Sh DESCRIPTION
48.Nm Shutdown
49provides an automated shutdown procedure for super-users
50to nicely notify users when the system is shutting down,
51saving them from system administrators, hackers, and gurus, who
52would otherwise not bother with such niceties.
53.Pp
54Available friendlinesses:
55.Bl -tag -width time
56.It Fl f
57.Nm Shutdown
58arranges, in the manner of
59.Xr fastboot 8 ,
60for the file systems
61.Em not to be
62checked on reboot.
63.It Fl h
64The system is halted at the specified
65.Ar time
66when
67.Nm shutdown
68execs
69.Xr halt 8 .
70.It Fl k
71Kick every body off.
72The
73.Fl k
74option
75does not actually halt the system, but leaves the
76system multi-user with logins disabled (for all but super-user).
77.It Fl n
78Prevent the normal
79.Xr sync 2
80before stopping.
81.It Fl r
82.Nm Shutdown
83execs
84.Xr reboot 8
85at the specified
86.Ar time .
87.It Ar time
88.Ar Time
89is the time at which
90.Nm shutdown
91will bring the system down and
92may be the word
93.Ar now
94(indicating an immediate shutdown) or
95specify a future time in one of two formats:
96.Ar +number ,
97or
98.Ar yymmddhhmm ,
99where the year, month, and day may be defaulted
100to the current system values.  The first form brings the system down in
101.Ar number
102minutes and the second at the absolute time specified.
103.It Ar warning-message
104Any other arguments comprise the warning message that is broadcast
105to users currently logged into the system.
106.It Fl
107If
108.Ql Fl
109is supplied as an option, the warning message is read from the standard
110input.
111.El
112.Pp
113At intervals, becoming more frequent as apocalypse approaches
114and starting at ten hours before shutdown, warning messages are displayed
115on the terminals of all users logged in.  Five minutes before
116shutdown, or immediately if shutdown is in less than 5 minutes,
117logins are disabled by creating
118.Pa /etc/nologin
119and copying the
120warning message there.  If this file exists when a user attempts to
121log in,
122.Xr login 1
123prints its contents and exits.  The file is
124removed just before
125.Nm shutdown
126exits.
127.Pp
128At shutdown time a message is written in the system log, containing the
129time of shutdown, who initiated the shutdown and the reason.
130A terminate
131signal is then sent to
132.Xr init
133to bring the system down to single-user state (depending on above
134options).
135The time of the shutdown and the warning message
136are placed in
137.Pa /etc/nologin
138and should be used to
139inform the users about when the system will be back up
140and why it is going down (or anything else).
141.Sh FILES
142.Bl -tag -width /etc/nologin -compact
143.It Pa /etc/nologin
144tells login not to let anyone log in
145.It Pa /fastboot
146tells
147.Xr rc 8
148not to run fsck when rebooting
149.El
150.Sh SEE ALSO
151.Xr login 1 ,
152.Xr wall 1 ,
153.Xr fastboot 8 ,
154.Xr halt 8 ,
155.Xr reboot 8
156.Sh BACKWARD COMPATIBILITY
157The hours and minutes in the second time format may be separated by
158a colon (``:'') for backward compatibility.
159.Sh HISTORY
160The
161.Nm
162command appeared in
163.Bx 4.0 .
164