1BEGIN { FS = "a" }
2{
3	n = split ($0, x, FS)
4	if (n != NF)
5		print "botch at ", NR, n, NF
6	for (i=1; i<=n; i++)
7		if ($i != x[i])
8			print "diff at ", i, x[i], $i
9}
10