Jan Engelhardt wrote: > There is (my default zone is /etc/localtime -> > /usr/share/zoneinfo/Europe/Berlin): > > $ TZ=GMT date +%s -d "`date '+%Y-%m-%d %H:%M:%S'`" > 1204325194 > $ date +%s > 1204321595 > > (now with not-so-fast typing! :)
:-) > I wanted to get the number of seconds since the start of the day. > > echo $[`date +%s` % 86400]; Note that the $[expression] syntax is deprecated and is scheduled for removal from a future version of the shell. Please convert to using the now standard $((expression)) syntax. echo $(( $(date +%s) % 86400 )); > unfortunately does not do the right thing — it would show > 82800 instead of 0 when it is (local) midnight. Midnight and noon are neither a.m. nor p.m. but midnight is considered the start of the day. Therefore normal convention would use a seconds range of 0-86399 seconds in any given day similar to 0-59 seconds in a minute. Do I understand that you want to use 1-86400? That would be like using 1-60 seconds in a minute, right? In which case I would simply special case the zero case and convert it to the max value specially. But I probably wouldn't do it. I can't think of any totally race free way to do this without invoking date multiple times. The problem is right around midnight we want to avoid having one invocation from before and one from after. My technique is to get the time once and then shape that single point in time as I need it so as to avoid any possibility of problems at midnight. But I don't see that as being too inefficient so I would simply invoke date several times and not worry about it. Perhaps someone else will have a better optimized strategy. nowseconds=$(date +%s) dateday=$(date -d "$nowseconds" +%F) # e.g. 2008-02-29 secondsatdaystart=$(date -d "$dateday" +%s) secondssincedaystart=$(( $nowseconds - $secondsatdaystart )) echo $secondssincedaystart That still treats midnight as 0 seconds since day start. I think that is the right thing to do but if you want it the other way then you could add a case. nowseconds=$(date +%s) dateday=$(date -d "$nowseconds" +%F) # e.g. 2008-02-29 secondsatdaystart=$(date -d "$dateday" +%s) secondssincedaystart=$(( $nowseconds - $secondsatdaystart )) case $secondssincedaystart in (0) secondssincedaystart=86400 ;; esac echo $secondssincedaystart I am also sure there are ways to optimize this further but this seemed good enough. I didn't test that very much but the numbers seemed reasonable to me at brief glance at them. Bob _______________________________________________ Bug-coreutils mailing list Bug-coreutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-coreutils
