It's easier than that... You should read perlrequick, perlretut, and perlre. ...it's a couple hours of reading, but as they say, "then you'll know."

Here's an example of how easy it can be to detect ascii values above 126, using a regular expression:

while( $string =~ m/([^\x01-\x7E]+)/g ) {
    print $1, "\n";
}
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