my $myresult = "";
    while(<$mystdout>){
        $myresult = "$myresult$_";
    }
[download]

That is usually written as:

    my $myresult = "";
    while(<$mystdout>){
        $myresult .= $_;
    }
[download]

Or as:

    my $myresult = join '', <$mystdout>;
[download]

Or as:

    local $/;
    my $myresult = <$mystdout>;
[download]