.TH TIMESYNC 8
.SH NAME
timesync \- synchronize the system clock to a time source
.SH SYNOPSIS
.B aux/timesync
[
.B -a
.I accuracy
]
[
.B -S
.I stratum
]
[
.B -s
.I netroot
]
[
.B -frnDdLilG
]
[
.I timeserver
]
.SH DESCRIPTION
.B Aux/timesync
synchronizes the system clock to a time source, by default a
file server.
The options are:
.TP
.B -f
synchronize to a file server.  If
.I timeserver
is missing, use
.BR /srv/boot .
.TP
.B -r
synchronize to the local real time clock,
.BR #r/rtc .
.TP
.B -L
used with
.B -r
to indicate the real time clock is in
local time rather than GMT.  This is
useful on PCs that also run the 
Windows OS.
.TP
.B -n
synchronize to an NTP server.  If
.I timeserver
is missing, dial the server
.BR udp!$ntp!ntp .
.TP
.B -D
print debugging to standard error
.TP
.B -d
put file containing last determined clock
frequency in directory
.IR dir ,
default
.BR /tmp .
.TP
.B -i
stands for impotent.
.I Timesync
announces what it would do but doesn't do it.
This is useful for tracking alternate time sources.
.TP
.B -a
specifies the
.I accuracy
in nanoseconds to which the
clock should be synchronized.  This determines
how often the reference clock is accessed.
.TP
.B -G
causes
.I timesync
to use a gps server (see
.IR gpsfs (8))
as a time source.
.TP
.B -s
causes
.I timesync
to listen for UDP NTP requests on the
network rooted at
.IR netroot .
Up to 4
.B -s
options are allowed.
.TP
.B -S
sets the stratum number to
.IR stratum .
.TP
.B -l
turns on logging to
.BR /sys/log/timesync .
.SH FILES
.TF /tmp/ts.<sysname>.<type>.timeserver
.TP
.B /tmp/ts.<sysname>.<type>.timeserver
where the last frequency guess is kept
.TP
.B /sys/log/timesync
log file
.SH SOURCE
.B /sys/src/cmd/aux/timesync.c