ref: 279f78a86cbff3f526fe1a1debd4d4f5766f96b0 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 }