foreach $network_if (@tcp_utilization_metrics) {
    local $if_name = $network_if;
    if ($network_if =~ /en/) {
        $network_if =~ substr ($network_if, 2, 0, "t");
    }

##</code><code>##

foreach $if_name (@tcp_utilization_metrics) {
    local $network_if = $if_name;
    if ($network_if =~ /en/) {
        $network_if =~ substr ($network_if, 2, 0, "t");
    }