Replacing lines in a file does not remove empty lines

Question

I've this function to remove lines from a txt file:

function replace_file($path, $string, $replace)
    {
        set_time_limit(0);

        if (is_file($path) === true)
        {
            $file = fopen($path, 'r');
            $temp = tempnam('./', 'tmp');

            if (is_resource($file) === true)
            {
                while (feof($file) === false)
                {
                    file_put_contents($temp, str_replace($string, $replace, fgets($file)), FILE_APPEND);
                }

                fclose($file);
            }

            unlink($path);
        }

        return rename($temp, $path);
    }

Usage: replace_file("file.txt", "line to remove", '');

It is working perfectly but it always keep an empty line at the end of the file.

Is it possible to solve that?

Any help would be appreciated.

Thanks!

It is typically considered correct to leave an empty line at the end of a file. https://stackoverflow.com/a/2287990/2562137 — OrderAndChaos, Jul 27 '18 at 16:17
If your only handling small files, then using [file()](http://php.net/manual/en/function.file.php) and array walk then implode into a file would work just the same, but a more optimal solution for both big and small files would be to [use a generator](https://stackoverflow.com/a/43053295/661872), you can't fix the issue with your current code as your using FILE_APPEND, and won't know if its the last line to trim the new line. — Lawrence Cherone, Jul 27 '18 at 16:27
@Sarcoma Why is that? (Technically speaking). I always remove it when I come across it; wondering if I should stop, lol. — J. Scott Elblein, Jul 27 '18 at 16:35
@J.ScottElblein It's a hang over from older systems that expect an empty line before EOF. In PHP it's part of PSR-2. — OrderAndChaos, Jul 27 '18 at 16:41
[`set_time_limit(0)`](https://php.net/set_time_limit) Setting that to zero is a REALLY bad idea within a function call. Functions shouldn't have side effects like that. — Mark Tomlin, Jul 27 '18 at 17:05

J. Scott Elblein · Answer 1 · 2018-07-29T02:54:52.107

1

If you're only looking to remove the empty line at the end, have a look at rtrim.

edited Jul 29 '18 at 02:54

answered Jul 27 '18 at 16:26

J. Scott Elblein

4,013
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score 1 · Answer 2 · answered Jul 27 '18 at 22:15

I've edited the function to be like that:

function replace_file($path, $string, $replace)
    {
        set_time_limit(0);

        if (is_file($path) === true)
        {
            $file = fopen($path, 'r');
            $temp = tempnam('./', 'tmp');

            if (is_resource($file) === true)
            {
                while (feof($file) === false)
                {
                    file_put_contents($temp, str_replace($string, $replace, fgets($file)), FILE_APPEND);
                    file_put_contents($temp,
                        implode('', file($path, FILE_SKIP_EMPTY_LINES)));
                }

                fclose($file);
            }

            unlink($path);
        }

        return rename($temp, $path);
    }

And now it works.

Replacing lines in a file does not remove empty lines

2 Answers2