System Administration Commands                            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 correc-
                     tions  if necessary. It is normally run once
                     a day by a cron job.

                     If  there   is   no   RTC   time   zone   or
                     /etc/rtcconfig  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 con-
                     figuration  file  /etc/rtcconfig  with  the
                     name  of  the specified zone and the current
                     GMT lag for that zone. If there is an exist-
                     ing   rtcconfig  file,  this  command  will
                     update it. If not, this command will  create
                     it.


FILES
     /etc/rtcconfig    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.



SunOS 5.11           Last change: 3 Oct 2003                    1






System Administration Commands                            rtc(1M)



ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Architecture                 x86                         
    
     Availability                 SUNWcsu                     
    


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






































SunOS 5.11           Last change: 3 Oct 2003                    2