ref: 279f78a86cbff3f526fe1a1debd4d4f5766f96b0 dir: /test/t.set0/
{$0 = $1; print; print NF, $0; print $2} {$(0) = $1; print; print NF, $0; print $2} { i = 1; $(i) = $i+1; print }