#!/bin/bash

# difference between two trees in size
#  assuming one tree has hardlinked files into the other tree

# Ken Chasse math att sizone dott org

[ -z "$2" ] && echo "Usage: $0 olddir newdir" && exit

echo "total MB	incr MB	   %age increase"

du -xkm "$1" "$2" |
expand - |
sort -t / -k2 -k1.9,16n |
gawk  "/$1/"'{ if (d==2) { print "*"d":",ls,"\t0","\t0\t",ld}
               ls=$1; ld=$2; t=$1; d=2;}
     '"/$2/"'{ d=1; p=int(($1/(t+.00001))*100); 
               gsub("'"$2"'","",$2);
               printf ("%6d\t%6d\t%6d\t%s\n", t, $1, p<9999?p:9999, $2); t=0 }' |
sort -t "	" -k2rn -k4