NAME
readclock - read the AT's real time clock
SYNOPSIS
readclock [-nwW2]
DESCRIPTION
Readclock reads the AT's real time clock and sets the
machine's time. It is usually the second thing done in
/etc/rc, the first thing is setting the time zone by sourc-
ing /etc/profile. This means that the clock is assumed to
tell the wall clock time. If you want to run the clock in
GMT then you can put TZ=GMT (or any other TZ value) in front
of the readclock command.
OPTIONS
-n Play-act, don't set the time nor change the calibration
data, just show what would be done.
-w Write the current time to the CMOS clock. Dangerous,
see BUGS. Don't forget to use TZ=GMT in front of read-
clock if the clock should run in GMT.
-W Like -w, but also sets the status registers of the CMOS
clock to their proper values. (For if the clock sud-
denly runs at an odd pace or has stopped and the BIOS
doesn't repair it.)
-2, Add 20 to any year before 2000. If your CMOS clock
year can't run past 2000, then you can set it to 1980
and use -2 to correct the year. Together with -w the
year minus 20 is written to the clock.
FILES
/etc/profile Timezone and other shell initialization
code.
SEE ALSO
date(1), utime(1).
BUGS
Reported to not work on some AT's.
May mess up the clock royally when setting it (-w). Only if
you have a very standard AT and you are not afraid of having
your CMOS setup reset to the default with a "checksum error"
should you use readclock to set the time of the CMOS clock.
You have been warned.
AUTHOR
Kees J. Bot (kjb@cs.vu.nl)