Issue/Introduction:
How to check and validate timezone data within Linux, with reference to daylight-saving.If a Crossbeam system is configured, via the standard cli, to a specific timezone (say Europe/Moscow) the customer may wish to understand the implications of this, particularly in terms of when changes will be made to allow for daylight savings.
Resolution:
The required data can be displayed using the Linux zdump command.
For example, if I was interested in knowing about daylight savings settings for the Moscow zone in the year 2011 I would use a command similar to this:
zdump -c 2013 -v Europe/Moscow | tail -n 20
Note the following:
- The year given (here 2013) should be a little after the year of interest (2011)
- The timezone name, of course, needs to match the required zone.
- The piped 'tail' command is optional but will suppress a lot of redundant data prior to the elements of interest. Potentiall the '-n 20' could require tweaking.
This command might produce output similar to this:
Europe/Moscow Sat Oct 25 22:59:59 2008 UTC = Sun Oct 26 02:59:59 2008 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 25 23:00:00 2008 UTC = Sun Oct 26 02:00:00 2008 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 28 22:59:59 2009 UTC = Sun Mar 29 01:59:59 2009 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 28 23:00:00 2009 UTC = Sun Mar 29 03:00:00 2009 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 24 22:59:59 2009 UTC = Sun Oct 25 02:59:59 2009 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 24 23:00:00 2009 UTC = Sun Oct 25 02:00:00 2009 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 27 22:59:59 2010 UTC = Sun Mar 28 01:59:59 2010 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 27 23:00:00 2010 UTC = Sun Mar 28 03:00:00 2010 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 30 22:59:59 2010 UTC = Sun Oct 31 02:59:59 2010 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 30 23:00:00 2010 UTC = Sun Oct 31 02:00:00 2010 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 26 22:59:59 2011 UTC = Sun Mar 27 01:59:59 2011 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 26 23:00:00 2011 UTC = Sun Mar 27 03:00:00 2011 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 29 22:59:59 2011 UTC = Sun Oct 30 02:59:59 2011 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 29 23:00:00 2011 UTC = Sun Oct 30 02:00:00 2011 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 24 22:59:59 2012 UTC = Sun Mar 25 01:59:59 2012 MSK isdst=0 gmtoff=10800
Europe/Moscow Sat Mar 24 23:00:00 2012 UTC = Sun Mar 25 03:00:00 2012 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 27 22:59:59 2012 UTC = Sun Oct 28 02:59:59 2012 MSD isdst=1 gmtoff=14400
Europe/Moscow Sat Oct 27 23:00:00 2012 UTC = Sun Oct 28 02:00:00 2012 MSK isdst=0 gmtoff=10800
The output should be fairly self-explanatory.