sub write_register {
my ($date,$client_ip,$client_imsi) = @_;

 $output=qx(snmpwalk -v2c -t1 -c $community $client_ip $snmp_fver 2>&1);
 chomp($output);
        if( $output eq "Timeout: No Response from $client_ip" ) {
        return; 
        }
        else{
                   my @result=split(/:/,$output);
                   if ($result[3]){
           $fver=$result[3];
                   $fver=~s/ //g;
                   $fver=~s/\n//g;

                   }else{
            exit;
            }
               }    # X

        if($bsid){
                system "sed -i '/$client_imsi/d' $path/leases_list.txt";
        system 'echo "'.$date.','.$client_ip.','.$client_imsi.','. $fver.'" >> '.$path.'/leases_list.txt';
        }
        
}

##</code><code>##

sub write_register
{
    my ($date, $client_ip, $client_imsi) = @_;

    $output = qx(snmpwalk -v2c -t1 -c $community $client_ip $snmp_fver 2>&1);
    chomp $output;

    if ($output eq "Timeout: No Response from $client_ip")
    {
        return; 
    }
    else
    {
        my @result = split /:/, $output;

        if ($result[3])
        {
            $fver =  $result[3];
            $fver =~ s/ //g;
            $fver =~ s/\n//g;
        }
        else
        {
            exit;
        }
    }   # X

    if ($bsid)
    {
        system "sed -i '/$client_imsi/d' $path/leases_list.txt";
        system 'echo "' . $date . ',' . $client_ip . ',' . $client_imsi . ',' .
                          $fver . '" >> ' . $path . '/leases_list.txt';
    }
}

##</code><code>##

if (condition)
{
    return;
}
else
{
    ...
}

##</code><code>##

return if condition;
...

##</code><code>##

sub write_register
{
    my ($date, $client_ip, $client_imsi, $bsid) = @_;
    chomp(my $output = qx(snmpwalk -v2c -t1 -c $community $client_ip $snmp_fver 2>&1));
    return if $output eq "Timeout: No Response from $client_ip";
    my @result = split /:/, $output;
    die unless $result[3];
    my $fver = $result[3];
       $fver =~ s/[ \n]//g;

    if ($bsid)
    {
        system "sed -i '/$client_imsi/d' $path/leases_list.txt";
        system 'echo "' . $date . ',' . $client_ip . ',' . $client_imsi . ',' .
                          $fver . '" >> ' . $path . '/leases_list.txt';
    }
}