| 1 | .TH READCLOCK 8
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| 2 | .SH NAME
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| 3 | readclock \- read the AT's real time clock
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| 4 | .SH SYNOPSIS
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| 5 | \fBreadclock\fP [\fB\-nwW2\fP]
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| 6 | .SH DESCRIPTION
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| 7 | .B Readclock
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| 8 | reads the AT's real time clock and sets the machine's time. It is usually
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| 9 | the second thing done in
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| 10 | .BR /etc/rc ,
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| 11 | the first thing is setting the time zone by sourcing
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| 12 | .BR /etc/profile .
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| 13 | This means that the clock is assumed to tell the wall clock time. If you
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| 14 | want to run the clock in GMT then you can put
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| 15 | .B "TZ=GMT"
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| 16 | (or any other TZ value) in front of the readclock command.
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| 17 | .SH OPTIONS
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| 18 | .TP
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| 19 | .B \-n
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| 20 | Play-act, don't set the time nor change the calibration data, just show what
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| 21 | would be done.
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| 22 | .TP
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| 23 | .B \-w
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| 24 | Write the current time to the CMOS clock. Dangerous, see
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| 25 | .BR BUGS .
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| 26 | Don't forget to use
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| 27 | .B "TZ=GMT"
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| 28 | in front of readclock if the clock should run in GMT.
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| 29 | .TP
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| 30 | .B \-W
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| 31 | Like
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| 32 | .BR \-w ,
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| 33 | but also sets the status registers of the CMOS clock to their proper values.
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| 34 | (For if the clock suddenly runs at an odd pace or has stopped and the BIOS
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| 35 | doesn't repair it.)
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| 36 | .TP
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| 37 | .BR \-2 ,
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| 38 | Add 20 to any year before 2000. If your CMOS clock year can't run past 2000,
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| 39 | then you can set it to 1980 and use
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| 40 | .B \-2
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| 41 | to correct the year. Together with
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| 42 | .B \-w
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| 43 | the year minus 20 is written to the clock.
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| 44 | .SH FILES
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| 45 | .TP 20n
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| 46 | /etc/profile
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| 47 | Timezone and other shell initialization code.
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| 48 | .SH "SEE ALSO"
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| 49 | .BR date (1),
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| 50 | .BR utime (1).
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| 51 | .SH BUGS
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| 52 | Reported to not work on some AT's.
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| 53 | .PP
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| 54 | May mess up the clock royally when setting it
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| 55 | .RB ( \-w ).
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| 56 | Only if you have a very standard AT and you are not afraid of having your
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| 57 | CMOS setup reset to the default with a "checksum error" should you use
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| 58 | .BR readclock
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| 59 | to set the time of the CMOS clock. You have been warned.
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| 60 | .SH AUTHOR
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| 61 | Kees J. Bot (kjb@cs.vu.nl)
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