timer problem (was: Re: [vdr] Re: vdr 1.3.25 thread problems)

Sergei Haller Sergei.Haller at math.uni-giessen.de
Thu Jun 2 11:56:10 CEST 2005


On Wed, 1 Jun 2005, Rainer Zocholl (RZ) wrote:

RZ>           date -u -d '1970-01-01 946684800 seconds' +"%Y-%m-%d %T %z"
RZ>           2000-01-01 00:00:00 +0000
RZ> 
RZ> 
RZ> I don't see why this is a "cheat" (= not intended way of usesage) 

they could have implemented a thing like 

   date -d "946684800"

THEN it would be intended. it would take the _unique_ point in time 
946684800 and print it as a string corresponding to this _unique_ point in 
time. The output would of course depend on your time zone or the option 
-u. But the input would not, since it is time zone independant.

as you can see on your own examples, the way it is implemented now 
_does_not_ convert the _unique_ point in time 1117634400 to the human 
readable format of this _unique_ point in time.

RZ> The man page example is missleading.
RZ> date will interpret the "1970-01-01" with the current timezone...
RZ> 
RZ> It must read:
RZ> # date     -d  "1970-01-01 UTC 1117634400 sec"
RZ> Wed Jun  1 16:00:00 CEST 2005
RZ> as the "-utc" relates to output.
RZ> # date -u  -d  "1970-01-01 UTC 1117634400 sec"
RZ> Wed Jun  1 14:00:00 UTC 2005

on the first sight, the option -u only changes the output, BUT it also 
changes the assumed timezone if no timezone is given.

so 
  date -u  -d  "1970-01-01 UTC 1117634400 sec"
  date -u  -d  "1970-01-01     1117634400 sec"
are the same:
  Wed Jun  1 14:00:00 UTC 2005
which is correct:
  date +%s -d "Wed Jun  1 14:00:00 UTC 2005"
  1117634400


RZ> But i still do not undestand why here is a 1h offset
RZ> if nothing is given. 
RZ> I would assuem that the timezone would be komensated
RZ> # date -d  "1970-01-01  1117634400 sec"
RZ> Wed Jun  1 15:00:00 CEST 2005

and you will never know, if you don't know which time zone "date"
assumes in the input.


        Sergei
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