Shell Programming and Scripting

if [ $* -eq 2 ]
then
echo "please enter more than two numbers"
exit 1
fi

total=0
for i in $*
do
total=`echo $(($total + $i))`
done

echo $total

total=0
n=$#
while [[ -n $1 ]]
do
   total=$(( total + $1 ))
   shift
done
echo "total=$total  average=$(($total/$n))"

echo "total=$total  average=$(($total/$n.0))"

if [[ $# -eq 2 || $# != [0-9] ]]

#!/usr/bin/env ksh
total=0
n=$#
while [[ -n $1 ]]
do
    if [[ -n ${1//[0-9]/}  ]]       # replace all digits in x and if result isn't empty, fail
    then
        echo "abort: invalid parameter entered: $1"
        exit 1
    fi

   total=$(( total + $1 ))
   shift
done

if (( $n > 0 ))    # prevent div by zero issues
then
    echo "total=$total  average=$(($total/$n))"
fi

exit