#!/bin/sh

#  Find path to gnu date program
$GNUDATE = defined $ENV{GNUDATE} ? $ENV{GNUDATE} : "date";

# Usage:  FormDate prefix suffix datespan [startdate]

if [ $# -lt 3 ] 
then
   echo `basename $0` 'prefix suffix datespan [startdate]'
   exit
fi

#  Store arguements in friendly variable names
prefix=$1
suffix=$2
datespan=$3
if [ $datespan -lt 0 ]
then
   del=-1
else
   del=1
fi

#  Determine start date
if [ $# -ge 4 ]
then
   startdate=`$GNUDATE -d"$4" +"%Y-%m-%d"`
else
   startdate=`$GNUDATE "+%Y-%m-%d"`
fi


#  Append start dates to argument
i=0
while [ $i -ne $datespan ]
do
   narg=`$GNUDATE "+%Y-%m-%d" -d " $startdate $i day "`
   if [ $del -lt 0 ]
   then
      arg="$prefix$narg$suffix $arg"
   else
      arg="$arg $prefix$narg$suffix"
   fi
   i=`expr $i + $del`
done

echo $arg
