Shell script to check if a string is a palindrome?

len=0

i=1

echo -n "Enter a String: "

read str

len=echo $str | wc -c

len=expr $len - 1

halfLen=expr $len / 2

while [ $i -le $halfLen ]

do

c1=echo $str|cut -c$i

c2=echo $str|cut -c$len

if [ $c1 != $c2 ] ; then

echo "string is not palindrome"

exit

fi

i=expr $i + 1

len=expr $len - 1

done

echo "String is Palindrome"