ref: 10e72d182aad860492f6ec2e80b0c05a4dc20b7a 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 }