One way forward here would be to give zdump more options to let the user specify the format. That way, everybody could use their own favorite format. One format might look something like this for America/Los_Angeles, assuming the default zdump window of -500 through 2499 CE UTC: -501-12-31 16:07:02 -07:52:58 0 LMT 1883-11-18 12:00 -08 0 PST 1918-03-31 03:00 -07 1 PDT 1918-10-27 01:00 -08 0 PST ... 2016-03-13 03:00 -07 1 PDT 2016-11-06 01:00 -08 0 PST ... 2499-03-08 03:00 -07 1 PDT 2499-11-01 01:00 -08 0 PST (The "1" and "0" are whether DST is in effect.) This completely characterizes the data and is more compact and easier to read than what zdump outputs now. Other formats might be preferable for other reasons. It might also be nice to output "PST8PDT,M3.2.0,M11.1.0" at the end, instead of that repetitive list of lines starting with the year 2007.