Nifty shell script of the day: calculating standard deviation

Here's his script, as written:

#!/bin/sh
# copyright(c) j. kotecha 2004 -- http://www.vidia.com/
# this file may be used without fee as long as the copyright 
# notice is kept the program is is "as is" and not warranted 
# for any purpose. Use at your own risk

M="0"
s="0"
v="0"
d="0"

if [ $# -eq 0 ]; then
  exit 1
fi

if [ $1 = "-m" ]; then
   M=$2
   shift 2
else
   M=0
fi

list=$*
count=$#

for i in $*
do
  d=`scriptbc -p 9 $i - $M`
  v=`scriptbc -p 9 $d \* $d`
  s=`scriptbc -p 9 $s + $v`
done

std="`scriptbc -p 9 $s / $count`"
std="`scriptbc -p 9 sqrt \( $std \)`"

echo $std

Great job, Josh!