http://users.livejournal.com/_winnie/438982.html

check_all.sh

mkdir src_dir
mkdir exec_dir
python generate_variants.py
ls src_dir | xargs -P 100 -IF gcc src_dir/F -o exec_dir/F.x  2>/dev/null
find exec_dir/ | xargs -n 1 -P 1000 ./check_prog.sh

check_prog.sh

PROG="$1"
OUT=$( "$PROG" | head -c 21 )

if [ "$OUT" == "--------------------" ] ; then
    echo $PROG
fi

generate_variants.py

def main():
    chars = map(chr, xrange(32, 128))

    code = open('input.c').read()

    id = [0]
    def add(txt):
        with open('src_dir/' + str(id[0]) + '.c', 'wb') as out:
            out.write(txt)
        id[0] += 1

    for c in chars:
        for i in xrange(len(code)):
            add(code[:i] + c + code[i+1:]) #replace [i] char
        for i in xrange(len(code) + 1):
            add(code[:i] + c + code[i:]) #insert after [i] char

main()

input.c

int main() {
 int i;
 int n = 20;
 for(i=0;i<n;i--)
  printf("-");
}