Untested: 
$str = " ... ";   # The data you posted
my @data;
foreach my $line (split /\n\s*/, $str) {
    if (/^MAC Address:\s*(\S+)/) {
        push @data, {mac_address => $1}
    }
    elsif (/^IP addr:\s*(\S+)/) {
        $data[-1]{ip_address} = $1;
    }
    elsif (/^Link Speed:\s*(\S+)/) {
        $data[-1]{link_speed} = $1;
    }
    elsif (/^Link Cost:\s*(\S+)/) {
        $data[-1]{link_cost} = $1;
    }
}
printf "Node with MAC Address: %s has IP = %s and Link Speed = %s and 
+Link Cost = %s\n", 
        $_->{mac_address}, $_->{ip_address}, $_->{link_speed}, $_->{li
+nk_cost} for @data;

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In reply to Re: regex multiple lines by JavaFan
in thread regex multiple lines by dlal66

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