Shell Programming and Scripting

 
#!/bin/sh
echo "\n"
 
echo -------- Squares on a chessboard Calculator -------"\n"
echo "Simply, this calculator will return the number of
squares on a chessboard, according to the size of
the square chosen\n"
 
echo "Please enter a square size (1-8)...\n"
read SQUARE_SIZE
 
NO_SQUARES=`expr $SQUARE_SIZE + 5`
echo $NO_SQUARES
exit 0

$ for n in 1 2 3; do
> echo $(( n * (n + 1) * ( 2*n + 1)))
> done
6
30
84
$

NO_SQUARES=$(( SQUARE_SIZE * (SQUARE_SIZE + 1) * ( 2*SQUARE_SIZE + 1)))

[user@host ~]# cat test.sh
#!/bin/bash
n=$1
echo $((((n * (n + 1) * ((2 * n) + 1)) / 6)))
[user@host ~]#
[user@host ~]# ./test.sh 5
55
[user@host ~]# ./test.sh 6
91
[user@host ~]# ./test.sh 8
204
[user@host ~]#