Shell Programming and Scripting

#!/bin/sh

fromdate=01.04.2010
todate=24.04.2010

from=`echo $fromdate | awk  -F\. '{print $3 OFS $2 OFS $1}'`
to=`echo $todate | awk  -F\. '{print $3 OFS $2 OFS $1}'`

./datecalc -a $to - $from

#!/bin/sh

fromdate=01.04.2010
todate=24.04.2010

from=`echo $fromdate | awk  -F\. '{print $3$2$1}'`
to=`echo $todate | awk  -F\. '{print $3$2$1}'`

START_DATE=`date --date=$from +"%s"`
END_DATE=`date --date=$to +"%s"`

DAYS=$((($END_DATE - $START_DATE) / 86400 ))
echo $DAYS

#!/bin/ksh
isodate()
{      # dd.mm.yyyy to yyyy-mm-dd
        indate="$1"
        oifs="$IFS"
        IFS="."
        values=($indate)
        IFS="$oifs"
        iso="${values[2]}-${values[1]}-${values[0]}"
        echo "$iso"
}

fromdate=$(isodate 01.04.2010)
todate=$(isodate 24.04.2010)
# datestr => epoc
epoc1=$(printf "%(%#)T"   "$fromdate")
epoc2=$(printf "%(%#)T"   "$todate")

# length of day (seconds) = 86400
((day=24*60*60))
echo $(( (epoc2-epoc1) /day))