ref: 2af227c88bbcf8d6c52eb5b3b3a677d88a281774 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 }