ref: 279f78a86cbff3f526fe1a1debd4d4f5766f96b0 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] }