ref: c0f4e97e4561ff42544e92512bbaf3d7d1f6a671 dir: /testdir/t.split3/
{ a = $0 " " $0 " " $0 if ($1 != "") n = split (a, x, "[" $1 "]") print n, x[1], x[2], x[3], x[4] }