# A and B are executables you want to compare, gen takes int 
# as command line arg. Usage: 'sh stress.sh'
for((i = 1; ; ++i)); do
    echo $i
    ./gen $i > int
    ./A < int > out1
    ./B < int > out2
    diff -w out1 out2 || break
    # diff -w <(./F2 < int) <(./F < int) || break
done