Switching crontab to Summer/Winter times


This page describes the steps needed to modify vocms077 crontab when Geneva time zone changes due to daylight saving time before and after winter. This procedure has to be done twice a year when the calendar marks the time change. This dates change from year to year so make sure you get the right date depending on what year you're in.


Daylight Saving Time (DST) is the practice of setting the clocks forward 1 hour from standard time during the summer months, and back again in the fall, in order to make better use of natural daylight. Usually the first sunday closest to November marks the end of "summer" (a.k.a. daylight saving) time in Switzerland, France, many other European nations, and many nations around the world.

A list of transition dates is available Here

Clocks are set back (Spring forward, Fall back) by one hour. For explicit help on this procedure, please see This link


This procedure must be completed from a valid user account with appropriate permissions at vocms077.cern.ch.

  • Login to vocms077 with your regular CERN account
  • Switch to authorized user (cmsst) (More info Here)
  • Backup the installed cron in case somehing goes wrong:
    crontab -l > /Some_safe_directory/crontab.bak
  • Open crontab in edition mode
    crontab -e
  • Scroll down to
    # Daylight saving scripts section
  • Uncomment the lines of the time that's starting and Comment (#) the lines of the time that is ending (For instance: If it's the end of fall, you should comment all lines under #Summer time and uncomment all lines under #Winter time
  • Save and install the new cron
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Topic revision: r2 - 2017-10-29 - MariaAcostaFlechas
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