UNIX for Dummies Questions & Answers

#!/bin/bash

VALUES=()

for ((N=1; N<150; N+=5))
do
        INDEX=$(( (N-1) / 5 ))
        VALUES[${INDEX}]=0
done

while read COL1 COL2 N REST
do
        INDEX=$(( (N-1) / 5 ))
        VALUES[$INDEX]=$((VALUES[$INDEX]+1))
        echo "$INDEX = [ ${VALUES[$INDEX]} ]"
done <<EOF
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
EOF

for ((N=1; N<150; N+=5))
do
        INDEX="$(( (N+1) / 5))"
        printf "%3d - %3d: %d\n" $N $((N+4)) ${VALUES[$INDEX]}
done