How to read only 5 last line of the text file in PHP?

Question

I have a file named file.txt which is update by adding lines to it.

I am reading it by this code:

$fp = fopen(\"file.txt\", \"r\");
$da         


        

Answer 1

Opening large files with file() can generate a large array, reserving a considerable chunk of memory.

You can reduce the memory cost with SplFileObject since it iterates through each line.

Use the seek method (of seekableiterator) to fetch the last line. You should then subtract the current key value by 5.

To obtain the last line, use PHP_INT_MAX. (Yes, this is a workaround.)

$file = new SplFileObject('large_file.txt', 'r');

$file->seek(PHP_INT_MAX);

$last_line = $file->key();

$lines = new LimitIterator($file, $last_line - 5, $last_line);

print_r(iterator_to_array($lines));