can any gentle man e mail me solution of the following problem? problem:write shell program to check whether the given number is a perfect number or not

You have two options. The first being to compare to a relatively short list fixed list of numbers that are know to be perfect. The second checks against he published math formula and is very processor intesive. http://pachome1.pacific.net.sg/~novelway/MEW2/lesson1.html if [ $num -lt 500 ] ; then if [ $num -eq 6 -o $num 28 -o $num 496 ] ; then echo "Perfect number found" else echo "Not a perfect number" fi else echo "Sorry $num out of range" fi

http://primes.utm.edu/glossary/page.php?sort=PerfectNumber Theorem: If 2k-1 is prime, then 2k-1 (2k-1) is perfect and every even perfect number has this form. It turns out that for 2k-1 to be prime, k must also be prime--so the search for Perfect numbers is the same as the search for Mersenne primes. Armed with this information it does not take too long, even by hand, to find the next two perfect numbers: 33550336 and 8589869056. See the first page on Mersennes below for a list of all know perfect numbers.