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30 .\" @(#)shutdown.8 8.2 (Berkeley) 4/27/95
31 .\"
32 .Dd September 12, 2016
33 .Dt SHUTDOWN 8
34 .Os
35 .Sh NAME
36 .Nm shutdown
37 .Nd close down the system at a given time
38 .Sh SYNOPSIS
39 .Nm
40 .Op Fl Ddfhknprvxz
41 .Op Fl b Ar bootstr
42 .Ar time
43 .Op Ar message ... | Ar -
44 .Sh DESCRIPTION
45 .Nm
46 provides an automated shutdown procedure for super-users
47 to nicely notify users when the system is shutting down,
48 saving them from system administrators, hackers, and gurus, who
49 would otherwise not bother with such niceties.
50 .Pp
51 Available friendlinesses:
52 .Bl -tag -width bootstr
53 .It Fl b Ar bootstr
54 The given
55 .Ar bootstr
56 is passed to
57 .Xr reboot 8
58 for the benefit of those systems that can pass boot arguments to the
59 firmware.
60 Currently, this only affects sun3 and sparc machines.
61 .It Fl d
62 .Nm
63 will pass the
64 .Fl d
65 flag to
66 .Xr reboot 8
67 or
68 .Xr halt 8
69 to request a kernel core dump.
70 If neither the
71 .Fl h
72 or
73 .Fl r
74 flags are specified, then
75 .Fl d
76 also implies
77 .Fl r .
78 .It Fl f
79 .Nm
80 arranges, in the manner of
81 .Xr fastboot 8 ,
82 for the file systems
83 .Em not to be
84 checked on reboot.
85 .It Fl h
86 The system is halted at the specified
87 .Ar time ,
88 using
89 .Xr halt 8 .
90 .It Fl k
91 Kick everybody off.
92 The
93 .Fl k
94 option
95 does not actually halt the system, but leaves the
96 system multi-user with logins disabled (for all but super-user).
97 .It Fl n
98 Prevent the normal
99 .Xr sync 2
100 before stopping.
101 .It Fl p
102 The system is powered down at the specified
103 .Ar time ,
104 using
105 .Xr poweroff 8 .
106 If the powerdown fails, or the system does not support software powerdown,
107 the system will simply halt instead.
108 .It Fl r
109 The system is rebooted at the specified
110 .Ar time ,
111 using
112 .Xr reboot 8 .
113 .It Fl v
114 To enable verbose messages on the console, pass
115 .Fl v
116 to
117 .Xr reboot 8
118 or
119 .Xr halt 8 .
120 .It Fl x
121 To enable debugging messages on the console, pass
122 .Fl x
123 to
124 .Xr reboot 8
125 or
126 .Xr halt 8 .
127 .It Fl z
128 To silence some shutdown messages on the console, pass
129 .Fl z
130 to
131 .Xr reboot 8
132 or
133 .Xr halt 8 .
134 .It Fl D
135 Prevents
136 .Nm
137 from detaching from the tty with
138 .Xr fork 2 Ns /
139 .Xr exit 3 .
140 .It Ar time
141 .Ar Time
142 is the time at which
143 .Nm
144 will bring the system down and
145 may be the word
146 .Ar now
147 or a future time in one of two formats:
148 .Ar +number ,
149 or
150 .Ar [[[[[cc]yy]mm]dd]hh]mm ,
151 where the century, year, month, day, and hour may be defaulted
152 to the current system values.
153 The first form brings the system down
154 .Ar number
155 minutes from the current time; the second brings the system down at the
156 absolute time specified.
157 If the century is not specified, it defaults to 1900 for years between 69
158 and 99, or 2000 for years between 0 and 68.
159 A leading zero in the
160 .Dq yy
161 value is
162 .Em not
163 optional.
164 .It Ar message ...
165 Any other arguments comprise the warning message that is broadcast
166 to users currently logged into the system.
167 .It Ar -
168 If
169 .Ar -
170 is supplied as the only argument after the time, the warning message is read
171 from the standard input.
172 .El
173 .Sh BEHAVIOR
174 .Pp
175 At intervals, becoming more frequent as apocalypse approaches
176 and starting at ten hours before shutdown, warning messages are displayed
177 on the terminals of all users logged in.
178 Five minutes before shutdown, or immediately if shutdown is in less
179 than 5 minutes, logins are disabled by creating
180 .Pa /etc/nologin
181 and copying the warning message there.
182 If this file exists when a user attempts to log in,
183 .Xr login 1
184 prints its contents and exits.
185 The file is removed just before
186 .Nm
187 exits.
188 .Pp
189 At shutdown time, a message is written in the system log containing the
190 time of shutdown, who initiated the shutdown, and the reason.
191 Next a message is printed announcing the start of the system shutdown hooks.
192 Then the shutdown hooks in
193 .Pa /etc/rc.shutdown
194 are run, and a message is printed indicating that they have completed.
195 After a short delay,
196 .Nm
197 runs
198 .Xr halt 8
199 or
200 .Xr reboot 8 ,
201 or sends a terminate
202 signal to
203 .Xr init 8
204 to bring the system down to single-user mode, depending on the choice
205 of options.
206 .Pp
207 The time of the shutdown and the warning message are placed in
208 .Pa /etc/nologin
209 and should be used to tell the users why the system is
210 going down, when it will be back up, and to share any other pertinent
211 information.
212 .Sh FILES
213 .Bl -tag -width /etc/rc.shutdown -compact
214 .It Pa /etc/nologin
215 tells
216 .Xr login 1
217 not to let anyone log in
218 .It Pa /fastboot
219 tells
220 .Xr rc 8
221 not to run
222 .Xr fsck 8
223 when rebooting
224 .It Pa /etc/rc.shutdown
225 System shutdown commands
226 .El
227 .Sh SEE ALSO
228 .Xr login 1 ,
229 .Xr wall 1 ,
230 .Xr fastboot 8 ,
231 .Xr halt 8 ,
232 .Xr init 8 ,
233 .Xr poweroff 8 ,
234 .Xr reboot 8 ,
235 .Xr rescue 8
236 .Sh BACKWARD COMPATIBILITY
237 The hours and minutes in the second time format may be separated by
238 a colon (``:'') for backward compatibility.
239 .Sh HISTORY
240 A
241 .Nm
242 command was originally written by Ian Johnstone for UNSW's modified
243 .At "6th Edn" ,
244 modified, and then incorporated in
245 .Bx 4.1 .