We have this string to retrieve date and time in clean format.
TIMESTAMP=$(date "+%Y%m%d%H%M")
Is there some inline code that we can use to round the minute to 5 down. So if it is 12:03 it will make it 12:00 and if it is 12:49 it will be 12:45
Thank you!
To do this you can subtract the minutes modulo 5 from the total minutes. To print it out:
echo "$(date "+%Y%m%d%H%M") - ($(date +%M)%5)" | bc
To save it to a variable:
my_var=$(echo "$(date "+%Y%m%d%H%M") - ($(date +%M)%5)" | bc)
This relies on your date format string remaining as it is now - a string of numbers.
Example output:
$ date "+%Y%m%d%H%M"
201404010701
$ echo "$(date "+%Y%m%d%H%M") - ($(date +%M)%5)" | bc
201404010700
A little string manipulation:
case $TIMESTAMP in
*[1234]) TIMESTAMP=${TIMESTAMP%?}0;;
*[6789]) TIMESTAMP=${TIMESTAMP%?}5;;
esac
${TIMESTAMP%?} removes the last character. Ref: http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion
Not exactly bash only but using dateutils' dround utility, it boils down to:
$ dround now -5m
2014-04-01T10:35:00
or with your format specifiers:
$ dround now -5m -f '%Y%m%d%H%M'
201404011035
Disclaimer: I am the author of that project.
You can use the integer division and multiply back to get the round value.
$ m=23
$ (( m /= 5, m *= 5 )) && echo $m
20
Integer division just return the integer part of the result, so in the case above is returning 4. Then multiplying by 5 gives 20.
In your case:
$ TIMESTAMP=$(date "+%Y%m%d%H%M")
$ echo $TIMESTAMP
201404011231
$ (( TIMESTAMP /= 5, TIMESTAMP *= 5 ))
$ echo $TIMESTAMP
201404011230
$ TIMESTAMP=$(date "+%Y%m%d%H%M")
$ echo $TIMESTAMP
201404011257
$ (( TIMESTAMP /= 5, TIMESTAMP *= 5 ))
$ echo $TIMESTAMP
201404011255
using the remainder operator the we can determine the number of excess minutes, that can then be subtracted from the original:
TIMESTAMP=$(date "+%Y%m%d%H%M")
(( TIMESTAMP -= TIMESTAMP%15 ))
echo $TIMESTAMP
this only works because both 100 and 60 are divisible by 5 if 15 minutes was wanted instead of 5 the expression would be more complex:
(( TIMESTAMP -= TIMESTAMP%100%5 ))
The solution of Fedorqui is very smart and versatile:
seconds=$(date +%s)
echo $seconds $(date --date="@$seconds" +%H:%M:%S) # say 1559449650 # 06:27:30
# (( seconds /= 3600, seconds *= 3600 )) # rounds to this hour
# (( seconds += 3600, seconds /= 3600, seconds *= 3600 )) # rounds to next hour
(( seconds += 1800, seconds /= 1800, seconds *= 1800 )) # rounds to next half of a hour
next_hour=$(date --date="@$seconds" +%H:%M:%S)
echo $seconds $next_hour # say 1559449800 06:30:00
