# Here be ***UNTESTED*** code
my %snr;
while ( my $line = shift @lines ) {
    chomp $line;
    if ( $line =~ m/SNR:\s+(\d+)\s+(\d+)/ ) {
        ( $snr{up}, $snr{down} ) = ( $1, $2 );
        last;
    }
}
print q{Upstream_SNR:}, $snr{up}, 
        q{ }, 
        q{Downstream_SNR:}, $snr{down},
        qq{\n};