SUMMARY: modify system time

Werner.Rost_at_zfboge.com
Date: 07/28/03

  • Next message: Yogesh Bhanu: "Summary advfs and defragmenting a domain" 
    Date: Mon, 28 Jul 2003 16:24:58 +0200
To: tru64-unix-managers@ornl.gov

    Thanks a lot to
       Jim Fitzmaurice [jpfitz@fnal.gov]
       Jay Leafey [jleafey@utmem.edu]
       Mark Scarborough [mscar-osf@cactus.org]
    for their hints. This list is very helpful.

    I realized Jays solution using a perl script:

    #!/usr/bin/perl -w
    ($mon,$day,$year,$hour,$min) = (localtime(time()+(60*60*2)))[4,3,5,2,1];
    $newdate = sprintf "%02u%02u%02u%02u%04u",
            $mon+1, $day, $hour, $min, $year+1900;

    print "date $newdate\n";
    exec "date $newdate";

    Jims solution:

    #!/bin/ksh
    DAY=`date +"%d"`
    MON=`date +"%m"`
    MIN=`date +"%M"`
    YEA=`date +"%Y"`
    HOR=`date +"%H"`
    HOU=`expr $HOR + 2`
    #
    # Make sure hour doesn't exceed 24.
    #
    if [ $HOU -ge 24 ]
    then
        HOU=`expr $HOU - 24`
        DAY=`expr $DAY + 1`
    fi
    #
    # Ensue HOU and DAY are two digit numbers.
    #
    case $HOU in
        ?) HOU=`echo 0$HOU` ;;
    esac
    #
    case $DAY in
        ?) DAY=`echo 0$DAY` ;;
    esac
    #
    SEC=`date +"%S"`
    #
    # Set date
    #
    /bin/date $MON$DAY$HOU$MIN$YEA.$SEC
    #
    exit
    #

    Marks two solutions:

    1) get 'gnudate' and use:

    $ gnudate --date="+2 hours"

    2) do the "timezone trick":

    (for me, in CST6CDT)
    $ date
    Fri Jul 25 10:10:09 CDT 2003
    $ TZ=CST4CDT date
    Fri Jul 25 12:10:24 CDT 2003

    It looks to me like you are probably in GMT-2 timezone. If so, you could
    do this:
    $ TZ=GMT-2 date
    Fri Jul 25 17:11:42 GMT 2003
    $ TZ=GMT-4 date
    Fri Jul 25 19:11:46 GMT 2003

    This trick very much depends on what timezone your system is set for so it
    is not exactly the best, most portable solution, but it does work if you
    are careful.

    ----------------------------------------------

    Original problem:

    I need a script which add 2 hours to the actual system time and then
    "correct" the system time:

    1. t = date (actual system time say 9:13h)

    2. t := t + 2 hours 9:13h --> 11:13h

    3. date = t (set system time to 11:13h)

    Maybe somebody has done this and can tell me how to do.

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