reboot.tproj/reboot.8

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  32 .\"     @(#)reboot.8    8.1 (Berkeley) 6/9/93
  33 .\" $FreeBSD: src/sbin/reboot/reboot.8,v 1.21 2002/12/27 12:15:33 schweikh Exp $
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  35 .Dd June 9, 1993
  36 .Dt REBOOT 8
  37 .Os
  38 .Sh NAME
  39 .Nm halt ,
  40 .Nm reboot
  41 .Nd stopping and restarting the system
  42 .Sh SYNOPSIS
  43 .Nm halt
  44 .Op Fl lnqu
  45 .Nm reboot
  46 .Op Fl lnq
  47 .Sh DESCRIPTION
  48 The
  49 .Nm halt
  50 and
  51 .Nm reboot
  52 utilities flush the file system cache to disk,
  53 send all running processes a
  54 .Dv SIGTERM
  55 (and subsequently a
  56 .Dv SIGKILL )
  57 and, respectively, halt or restart the system.
  58 The action is logged, including entering a shutdown record into the
  59 .Xr wtmp 5
  60 file.
  61 .Pp
  62 When the system is halted with the halt command, the system is powered off.
  63 .Pp
  64 The options are as follows:
  65 .Bl -tag -width indent
  66 .It Fl l
  67 The halt or reboot is
  68 .Em not
  69 recorded in the system log.
  70 This option is intended for applications such as
  71 .Xr shutdown 8 ,
  72 that call
  73 .Nm reboot
  74 or
  75 .Nm halt
  76 and log this themselves.
  77 .It Fl n
  78 The file system cache is not flushed.
  79 This option should probably not be used.
  80 .It Fl q
  81 The system is halted or restarted quickly and ungracefully, and only
  82 the flushing of the file system cache is performed (if the
  83 .Fl n
  84 option is not specified).
  85 This option should probably not be used.
  86 .It Fl u
  87 The system is halted up until the point of removing system power, but waits
  88 before removing power for 5 minutes so that an external UPS
  89 (uninterruptible power supply) can forcibly remove power.
  90 This simulates a dirty shutdown to permit a later automatic power on. OS X uses
  91 this mode automatically with supported UPSs in emergency shutdowns.
  92 .El
  93 .Pp
  94 Normally, the
  95 .Xr shutdown 8
  96 utility is used when the system needs to be halted or restarted, giving
  97 users advance warning of their impending doom and cleanly terminating
  98 specific programs.
  99 .Sh SIGTERM TO SIGKILL INTERVAL
 100 The
 101 .Dv SIGKILL
 102 will follow the
 103 .Dv SIGTERM
 104 by an intentionally indeterminate period of time.
 105 Programs are expected to take only enough time to flush all dirty data and exit.
 106 Developers are encouraged to file a bug with the OS vendor, should they encounter an issue with this functionality.
 107 .Sh SEE ALSO
 108 .Xr wtmp 5 ,
 109 .Xr shutdown 8 ,
 110 .Xr sync 8
 111 .Sh HISTORY
 112 A
 113 .Nm reboot
 114 utility appeared in
 115 .At v6 .