Daylight Saving

[Frozen North]

On any Unix style system, the man pages for tzfile and tzset will give the details on how UTC time (which is what the machine's real time clock always uses) is changed to local time given the current time, date, and political region.

I'm not sure, but I believe that the tzfile is the most frequently updated software component under Linux. It changes every time a political entity somewhere modifies its local rules for daylight savings adjustments.

Long ago, the famed science/SF author Arthur C. Clarke predicted that one day people everywhere would dump local time and switch to UTC (then called GMT) for everyday usage. Perhaps this prediction, from the same person who predicted the Web and a tablet browser thirty years ahead of its invention, may yet come true.