Shell Programming and Scripting

date1=$1
date2=$2

#verify dates
if ! date -d "$date1" 2>&1 > /dev/null ;
    then echo "first date is invalid" ; exit 1
fi
if ! date -d "$date2" 2>&1 > /dev/null ;
    then echo "second date is invalid" ; exit 1
fi

#set current and end date
current=$(date -d "$date1")
end=$(date -d "$date2 ")

#loop over all dates
while [ "$end" != "$current" ]
do
    current=$(date -d "$current +1 day")
    echo $current
done

#!/bin/ksh93

date1="20130714"
date2="20130717"

startdate=${date1:0:4}"-"${date1:4:2}"-"${date1:6:2}
i=0

while :
do
     (( i++ ))
     datex=$(printf "%(%Y%m%d)T\n" "${startdate} + $i day")
     (( datex == date2 )) && break
     printf "%s\n" $datex
done