A small piece of bash script that will calculate the prime factors, given a number
factors()
{
num=$1
sqrt=`echo "sqrt($num)" | bc`
for (( i=$sqrt;$i>=2;i-- ))
do
if [[ `echo $num % $i | bc` -eq 0 ]]
then
echo "$i `echo $num/$i | bc`"
fi
done
}