#! /usr/bin/ksh

awk '{ if( $0 ~ /^,/ ) { printf "%s 1\n",$0 } else { printf "%s 0\n",$0 } }' file | while read
line ind
do
  if [ $ind -eq 0 ]
  then
     echo $var
     var=""
  fi
  var=$var$line
done
echo $var

exit 0

a=1
b=100,200,300,400,500,600
c=700,800
d=900

while read LINE
do
echo ${LINE}|grep -qE "^,+"
if [ $? -eq 0 ] 
then
   echo "${LINE}\c"
else
   echo "\n${LINE}\c"
fi
done<input_file
echo

sed -e 'H;$!d;x;s/\n,/,/g' file > newfile

#! /bin/bash

while read line; do
 [[ $line == ,* ]] && {
  printf "%s" "$line"
 } || {
  printf "\n%s" "$line"
}
done; printf "\n"