ref: 916fa4b8f99ff33340a5b9f018cd2a67c5fa49c4 dir: /test/t.split3/
{ a = $0 " " $0 " " $0 if ($1 != "") n = split (a, x, "[" $1 "]") print n, x[1], x[2], x[3], x[4] }