Thank you for the welcome and the very clear explanation! This worked brilliantly for me (and probably saved me a lot of time in the future).

Just out of curiosity, I went back and tried to solve the original problem with the regex after your tip about the "while" element only reading one line. You were absolutely right, and I should have been writing the following: 

open( FILE, "C:/Users/li/data_collection/posts/165644996453.html" ) ||
+ die "couldn't open\n";

while ( <FILE> ) {
    $data .= $_;
}

if ( $data =~ m/(?<=<p>)(.*)(?=<\/p>\s+<footer>)/g ) {
    print "$1\n";
 
}

[download]
(code taken from dsb's answer in Re: Apply regex to entire file, not just individual lines ?).

Thanks again!

In reply to Re^2: Matching regular expression over multiple lines by Maire
in thread Matching regular expression over multiple lines by Maire

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