Even outside the debugger, you can establish a warnings handler:

#!/usr/bin/perl

use warnings;
use strict;


my $sod='ip6 is used for...';
my $i=0;
my @baza_tek=qw( (?^u:ip(\d)) "internet_protocol-$1$2" );

{
    local $SIG{__WARN__} = sub {
        warn @_;
        warn "\$baza_tek[$i] is '$baza_tek[$i]";
        my $j = $i + 1;
        warn "\$baza_tek[$j] is '$baza_tek[$j]";
    };
    $sod=~s#$baza_tek[$i]#$baza_tek[$i+1]#gee;
}

[download]

And the reason $2 is undefined is that your regular expression has only one capture group, (\d).

In reply to Re^2: On error, how to show the regexp values? (tracing warnings) by Anonymous Monk
in thread Tracing warnings: how to show the regexp values? by nikolay

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