ref: 52a6023c85229ee680e0cb53df168cac214a915e dir: /test/t.split9a/
BEGIN { FS = "a" } { n = split ($0, x, FS) if (n != NF) print "botch at ", NR, n, NF for (i=1; i<=n; i++) if ($i != x[i]) print "diff at ", i, x[i], $i }