Re: [tz] How to compute the moment of the next DST change

On 02/04/13 09:58, Simon Perreault wrote:

I want to write a cron job or similar that activates one week prior to daylight saving time changes. (Or, more generically, one week prior to any time jumps, for any reason, DST or else.)

Any pointers?

I have looked at the usual places: POSIX time functions, various date/time modules on CPAN, etc. Nothing seems to do that computation. Do I need to parse the tz database myself?

If you're on Linux: TZ1=$(date +%Z) TZ2=$(date =d 'next week' +%Z) if [ $TZ1 != $TZ2 ]; then echo clocks change next week fi You can also use localtime(3) with the current time and the current time plus 7*24*2600 and compare the tm_hour field. jch