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28 .\" @(#)shutdown.8 8.2 (Berkeley) 4/27/95
37 .Nd "close down the system at a given time"
50 .Op Ar warning-message ...
55 utility provides an automated shutdown procedure for super-users
56 to nicely notify users when the system is shutting down,
57 saving them from system administrators, hackers, and gurus, who
58 would otherwise not bother with such niceties.
60 The following options are available:
61 .Bl -tag -width indent
63 The system is halted at the specified
66 The system is halted and the power is turned off
67 (hardware support required)
71 The system is rebooted at the specified
78 does not actually halt the system, but leaves the
79 system multi-user with logins disabled (for all but super-user).
86 options are specified,
92 instead of sending a signal to
97 option is specified, prevent the file system cache from being flushed by passing
103 This option should probably not be used.
108 will bring the system down and
109 may be the case-insensitive word
111 (indicating an immediate shutdown) or
112 a future time in one of two formats:
116 where the year, month, and day may be defaulted
117 to the current system values.
118 The first form brings the system down in
120 minutes and the second at the absolute time specified.
121 .It Ar warning-message
122 Any other arguments comprise the warning message that is broadcast
123 to users currently logged into the system.
127 is supplied as an option, the warning message is read from the standard
131 At intervals, becoming more frequent as apocalypse approaches
132 and starting at ten hours before shutdown, warning messages are displayed
133 on the terminals of all users logged in.
135 shutdown, or immediately if shutdown is in less than 5 minutes,
136 logins are disabled by creating
139 warning message there.
140 If this file exists when a user attempts to
143 prints its contents and exits.
149 At shutdown time a message is written to the system log, containing the
150 time of shutdown, the person who initiated the shutdown and the reason.
151 The corresponding signal is then sent to
153 to respectively halt, reboot or bring the system down to single-user state
154 (depending on the above options).
155 The time of the shutdown and the warning message
158 and should be used to
159 inform the users about when the system will be back up
160 and why it is going down (or anything else).
162 A scheduled shutdown can be canceled by killing the
171 created will be removed automatically.
173 When run without options, the
175 utility will place the system into single user mode at the
181 is equivalent to running:
182 .Bd -literal -offset indent
186 .Bl -tag -width /var/run/nologin -compact
187 .It Pa /var/run/nologin
190 not to let anyone log in
193 Reboot the system in 30 minutes and display a warning message on the terminals
194 of all users currently logged in:
196 .Dl # shutdown -r +30 \&"System will reboot\&"
198 The hours and minutes in the second time format may be separated by
199 a colon (``:'') for backward compatibility.