rtc(1M)

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  com-
           mand 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  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Architecture                | x86                         |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|

SEE ALSO

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