Project Euler 8 - Math Makes Things Better

# A quick script to find the largest product of five consecutive digits

# Set up our variables

DIGIT_STR=73167176519225119674426574742355349194934969239574788518438581294949595833471852952276689664452316173111217223831136222989343362766144866452382712188399827466572785224352586415722155397536978179778451693219784686224828397224137968652142124122758866688116427171479924442965674813919123162824586178664583591245665294765456828489128836321655444362979927244913387599116983572972571636269561852
POSITION=0
LEN=5
z=10000

echo We have ${#DIGIT_STR} digits to process

# Let's pull out our five digit substrings
# Code samples:
# z=`expr substr $string $position $length`
# echo ${DIGIT_STR:0:5}
# let "var += 5"
# TEST=`echo "76843" | grep -o . | sort -nr | tr -d '\n'`

while ((z >= 10000 ))
do
{
    z=${DIGIT_STR:$POSITION:$LEN}
    let "POSITION += 1"
    echo $z | grep -o . | sort -nr | tr -d '\n'
    echo

}
done