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28 .\" @(#)shutdown.8 8.2 (Berkeley) 4/27/95
36 .Nd "close down the system at a given time"
49 .Op Ar warning-message ...
53 utility provides an automated shutdown procedure for super-users
54 to nicely notify users when the system is shutting down,
55 saving them from system administrators, hackers, and gurus, who
56 would otherwise not bother with such niceties.
58 The following options are available:
59 .Bl -tag -width indent
61 The system is halted at the specified
64 The system is halted and the power is turned off
65 (hardware support required)
69 The system is rebooted at the specified
76 does not actually halt the system, but leaves the
77 system multi-user with logins disabled (for all but super-user).
90 instead of sending signal to
95 is specified, prevent the file system cache from being flushed by passing
101 This option should probably not be used.
106 will bring the system down and
109 (indicating an immediate shutdown) or
110 specify a future time in one of two formats:
114 where the year, month, and day may be defaulted
115 to the current system values.
116 The first form brings the system down in
118 minutes and the second at the absolute time specified.
119 .It Ar warning-message
120 Any other arguments comprise the warning message that is broadcast
121 to users currently logged into the system.
125 is supplied as an option, the warning message is read from the standard
129 At intervals, becoming more frequent as apocalypse approaches
130 and starting at ten hours before shutdown, warning messages are displayed
131 on the terminals of all users logged in.
133 shutdown, or immediately if shutdown is in less than 5 minutes,
134 logins are disabled by creating
137 warning message there.
138 If this file exists when a user attempts to
141 prints its contents and exits.
147 At shutdown time a message is written to the system log, containing the
148 time of shutdown, the person who initiated the shutdown and the reason.
149 Corresponding signal is then sent to
151 to respectively halt, reboot or bring the system down to single-user state
152 (depending on the above options).
153 The time of the shutdown and the warning message
156 and should be used to
157 inform the users about when the system will be back up
158 and why it is going down (or anything else).
160 A scheduled shutdown can be canceled by killing the
169 created will be removed automatically.
171 When run without options, the
173 utility will place the system into single user mode at the
177 .Bl -tag -width /var/run/nologin -compact
178 .It Pa /var/run/nologin
179 tells login not to let anyone log in
182 The hours and minutes in the second time format may be separated by
183 a colon (``:'') for backward compatibility.