Basic stats from stdin

stats.sh

#!/bin/bash

# Quick hacky script that computes basic statistics from a single
# column of numbers from stdin - inspired by the CouchDB _stats reducer

input=`cat`

sum=`echo "$input" | awk '{sum+=$1} END {print sum}'`
count=`echo "$input" | awk '{} END {print NR}'`
min=`echo "$input" | awk '{if (NR == 1 || $1 < min) min=$1} END {print min}'`
max=`echo "$input" | awk '{if (NR == 1 || $1 > max) max=$1} END {print max}'`
mean=`echo "$input" | awk '{sum+=$1; array[NR]=$1} END {print sum/NR}'`

# Stolen from http://www.commandlinefu.com/commands/view/1661/display-the-standard-deviation-of-a-column-of-numbers-with-awk
stddev=`echo "$input" | awk '{sum+=$1; array[NR]=$1} END {for(x=1;x<=NR;x++){sumsq+=((array[x]-(sum/NR))**2);}print sqrt(sumsq/NR)}'`

echo "sum:                $sum"
echo "count:              $count"
echo "min:                $min"
echo "max:                $max"
echo "mean:               $mean"
echo "standard deviation: $stddev"