READCLOCK(8)READCLOCK(8)NAMEreadclock - read the AT's real time clock
SYNOPSISreadclock [-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 set‐
ting the time zone by sourcing /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 readclock 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 suddenly 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 ALSOdate(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)
READCLOCK(8)
