man/man1m/rtc.1m

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 rtc 1M "3 Oct 2003" "SunOS 5.11" "System Administration Commands"
 NAME
rtc - provide all real-time clock and GMT-lag management
 SYNOPSIS

/usr/sbin/rtc [-c] [-z zone-name]


 DESCRIPTION

On x86 systems, the rtc command reconciles the difference in the way that
time is established between UNIX and MS-DOS systems. UNIX systems utilize
Greenwich Mean Time (GMT), while MS-DOS systems utilize local time.

Without arguments, rtc displays the currently configured time zone
string. The currently configured time zone string is based on what was last
recorded by rtc-z zone-name.

The rtc command is not normally run from a shell prompt; it is generally
invoked by the system. Commands such as date(1) and rdate(1M),
which are used to set the time on a system, invoke /usr/sbin/rtc -c
to ensure that daylight savings time (DST) is corrected for properly.
 OPTIONS

-c

This option checks for DST and makes corrections if necessary. It is
normally run once a day by a cron job.
If there is no RTC time zone or /etc/rtc_config file, this option
will do nothing.


-z zone-name

This option, which is normally run by the system at software installation time,
is used to specify the time zone in which the RTC is to be maintained. It
updates the configuration file /etc/rtc_config with the name of the
specified zone and the current GMT lag for that zone. If there is an
existing rtc_config file, this command will update it. If not, this
command will create it.


 FILES

/etc/rtc_config

The data file used to record the time zone and GMT lag. This file is
completely managed by /usr/sbin/rtc, and it is read by the kernel.


 ATTRIBUTES

See attributes(5) for descriptions of the following attributes:


ATTRIBUTE TYPEATTRIBUTE VALUE
Architecturex86


 SEE ALSO

date(1), rdate(1M), attributes(5)