Ndtyjky

I have two text file, one contains a previously got content from a website, the other text file is updated (append) with new content.

Old text file:
This is a sunny day.

New text file:
I enjoy playing outside. This is a sunny day.

I want to cut out the part: "I enjoy playing outside."
Put it in a variable, do something with it.

Then the old text file should be like this:
I enjoy playing outside. This is a sunny day.

Yet again the new updated file just now looks like this:
Well, I met people, they were fun! I enjoy playing outside. This is a sunny day.

So this time I want to cut out: "Well, I met people, they were fun!"
Put it in a variable, do something with it.

$old_file = file_get_contents('old.txt');



$page = file_get_contents('https://www.website.com/');

$doc = new DOMDocument();

$doc->loadHTML($page);

$divs = $doc->getElementsByTagName('div');

foreach($divs as $div) {

    if ($div->getAttribute('class') === 'feels') {

        $news = preg_replace(array('/s{2,}/', '/[tn]/'), ' ', $div->nodeValue);

    }

}

file_put_contents('new.txt', $news);

Now I have (old) content in old.txt and I have $news variable with updated content, if I have a $diff variable which contains the difference of the two text thats enough for me.

$diff= str_replace($old_file , '', $news);

not working...

Thanks