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bash: time difference and calculate the mid day of the day?

Hello,

In bash how to make the time difference and calculate the mid day of the day?

Quote:

Originally Posted by frenchn00b (Post 3528503)

Hello,

In bash how to make the time difference and calculate the mid day of the day?

solved, fast.
I wanna share it actually.

So all in one :

Code:

#!/bin/bash

weatherget  -s XXXXXX --metric > /tmp/weatherindi.tmp

timegot1=` cat /tmp/weatherindi.tmp   | grep Sunrise |  cut -d':' -f2-4 `

timegot2=` cat /tmp/weatherindi.tmp | grep Sunset |  cut -d':' -f2-4 `

start=`date +%s -d "$timegot1"`

end=`date +%s -d "$timegot2"`

timediff=`echo "$end - $start" | bc`

timediffsur2=`echo "($end - $start)/2" | bc`

timediffmid=`echo "$start + $timediffsur2" | bc`

thehour=`date +%H --date=@"$timediff"`

themin=`date +%M --date=@"$timediff" `

themiddayh=`date +%H --date=@"$timediffmid" `

themiddaym=`date +%M --date=@"$timediffmid" `

echo "`date +%H:%M --date=@$start`  `date +%H:%M --date=@$end`   ${thehour}H${themin} and the mid day is  ${themiddayh}H$themiddaym"

Ummm---the "mid day" of the day--AKA middle of the day--is 12:00 noon!! The time of sunrise and sunset is variable, but a day is defined by the clock and the calendar.

Perhaps you mean the time at which the sun is directly overhead? No--that occurs only at the equinox.

The time at which the maximum elevation angle of the sun is exactly equal to the latitude? No--that only happens at the solstice.

???

Quote:

Originally Posted by pixellany (Post 3528520)

I meant sun at max. overhead, so I divided sunset - sunrise / 2 ;)
solstice, equinox ...

what s the equation then to get max. sun, max UV point?