On Mon 04 Dec 2023 at 15:36:32 (-0500), Greg Wooledge wrote: > I classify time zone names into three historic eras. In the oldest era, > you have zone names like EST5EDT which are composed of three pieces. > The first piece, EST, is the zone's name when the clock is "normal" (not > daylight saving or summer time). The second piece, 5, is the number > of hours behind GMT the clock is (normally). The third piece, EDT, is > the zone's name when daylight saving time is in effect. > > In the second era, zone names look like "US/Eastern". The piece on the > right hand side is a component of the piece on the left. I'm uncertain > whether the pieces on the left are always country codes, or if there's > some other arrangement. > > In the modern era, zone names look like "America/Chicago". The piece on > the left is a continent (or other large geographic region, e.g. "Pacific"), > and the piece on the right is a major city, preferably *the* major city, > which exemplifies the specific time zone in question. > > For you and me, the current era time zone name is "America/New_York". > This is how the Debian installer sets the localtime symlink, and is > what we should be using if we have to set it ourselves. > > I personally find "US/Eastern" the easiest to grasp, and I'm sad that > this pattern fell out of fashion, for whatever reason. Whenever I tell > people on the Internet (who may not be Linux users) what time zone I'm > in, I always go with "US/Eastern". It's just so *clear*.
Because they don't work historically; for example, say you live in Wayne Co, KY: /usr/share/zoneinfo$ for j in America/Kentucky/*; do TZ="$j" date -d '@907654321'; done Tue Oct 6 02:12:01 EDT 1998 Tue Oct 6 01:12:01 CDT 1998 /usr/share/zoneinfo$ for j in America/Kentucky/*; do TZ="$j" date -d '@987654321'; done Thu Apr 19 00:25:21 EDT 2001 Thu Apr 19 00:25:21 EDT 2001 /usr/share/zoneinfo$ Cheers, David.
