ref: c3eea8755d4adbf3dc4cb9bda166a9e02c2064b5 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] }