Raymond Pete wrote: > I believe I have come across a small bug in the date command when daylight > savings time is in the process of being run.
Thank you for the report. But what you are describing looks like an incorrect expectation of behavior to me. > date --set "7 NOV 2010" > -->Sun Nov 7 00:00:01 EDT 2010 You don't need to actually set the date and mess with the system clock. Just use --date and have date interpret the date string. It would make for a more reliable example. > date --date="+1 day" > -->Sun Nov 7 23:00:40 EST 2010 I assume that EDT and EST here are US/Eastern DST and US/Eastern standard time? Better to use 'date -R' to produce numeric values that are not ambiguous. $ TZ=US/Eastern date -R -d "Sun, 07 Nov 2010 00:00:01 -0400 +1 day" Sun, 07 Nov 2010 23:00:01 -0500 > It would appear in Eastern time zone case there is a small 2 hour window of > error here whereby the date command has set the zone before it is actually > supposed to be set. I have seen this with all time zone shifts. Noticed > first last weekend when BST went to GMT. I don't understand. "7 NOV 2010" doesn't have a time associated with it and so the zero hour (midnight) is used. $ zdump -v US/Eastern | grep 2010 US/Eastern Sun Nov 7 05:59:59 2010 UTC = Sun Nov 7 01:59:59 2010 EDT isdst=1 gmtoff=-14400 US/Eastern Sun Nov 7 06:00:00 2010 UTC = Sun Nov 7 01:00:00 2010 EST isdst=0 gmtoff=-18000 November 7th at midnight is still within daylight savings time. Then you say "+1 day" which adds 24 hours to the current clock time and produces a time that is 24 hours later but *after* US/Eastern has changed to standard time. "Spring forward and Fall back." If you were expecting it to be midnight on the next day then you have forgotten that there is an extra hour inserted in the Fall when the clocks are turned back one hour. > Could be a known bug.. if so, sorry to trouble you guys. I see no bug here. Please explain if I missed something. See also this reference for more information: http://www.gnu.org/software/coreutils/faq/#The-date-command-is-not-working-right_002e Bob
