perl -e '
  $t=time;
  @l=localtime($t);
  @g=gmtime($t);
  $d=$l[2]-$g[2]+($l[1]-$g[1])/60;
  $gd=$g[3]+$g[4]*31+$g[5]*365;
  $ld=$l[3]+$l[4]*31+$l[5]*365;
  if($gd<$ld){$d+=24};
  if($gd>$ld){$d-=24}
print ($d."\n")'
2

perl -e 'if((localtime)[8]){print"yes"}else{print "no"}'
yes

7 thoughts on “Time offset in Unix”

1. Laurent Schneider Post authorMarch 30, 2011 at 18:09

   actually this was a tentative to improve
   echo $(($(date +%H)-$(date -u +%H)))
   because if “date” is executed twice, once at 17:59:59.999999999999 and once at 18:00:00.00000000001, you could hit a bug !
2. Laurent Schneider Post authorMarch 30, 2011 at 18:28

   I will need to fix this until midnight, duh…

   midnight bug and timezone with minutes fixed
3. Karoly March 30, 2011 at 19:08

   In my rss reader ist the first version, what you wrote as oneliner in perl.
   What is the problem with them?

   Ps: This is what i say every time to the newbies. Perl, awk, all the unix tools are powerful, that you can’t believe it. Try it, then you understand it. ( I don’t say it you, of course. )
4. Laurent Schneider Post authorMarch 31, 2011 at 09:28

   if you live in Zurich, at 1am in Summer you should get +2 and not -22
5. Karoly March 31, 2011 at 09:50

   Sure, you have right. I don’t live in Switzerland, and I don’t tested it at midnight.
   Maybe the best solution: You make a cronjob, which is run at 2:15. Then you have always the right offset.

   Ps: I’m currently in Germany. I was only once in Zurich. It is nice. Some friends of me living there.
6. Colin 't Hart March 31, 2011 at 09:58

   What’s wrong with just
   date +%z’
   ?
7. Laurent Schneider Post authorMarch 31, 2011 at 11:01

   This is OS specific.
   

   
   $ uname -srv
   AIX 3 5
   $ date +%z
   CEST
   
   $ uname -srv
   SunOS 5.10 Generic_142900-04
   $ date +%z
   +0200