Normalize new line of large text file.

normalize-newline-large-txt-file.php

<?php
/**
 * Normalize new line from anything (CR, CRLF) to be LF only.  
 * This will be replace new line from a file, line by line.
 */


// your file.
$textFile = '/path/to/my/file.txt';

// maximum execution time should be increased depend on amount of lines in file.
set_time_limit(90);

// that's all, no need to modify below.
// prevent overwrite temp file.
if (is_file($textFile . '.tmp')) {
  // if temp file is currently exists.
  throw new \Exception('Temporary file is currently exists, please make sure and delete it before continue.');
  exit();
}

$read = fopen($textFile, 'r');
$write = fopen($textFile . '.tmp', 'w');
if ($read && $write) {
    while (!feof($read)) {
        $line = fgets($read);
        $line = preg_replace('~(*BSR_ANYCRLF)\R~', "\n", $line);
        fwrite($write, $line);
    }
}// endif;

// finish. --------------
if ($read) {
    fclose($read);
}
if ($write) {
    fclose($write);
}
unset($read, $write);

if (is_file($textFile . '.tmp')) {
    rename($textFile . '.tmp', $textFile);
    // make sure that temporary file is not exists.
    if (is_file($textFile . '.tmp')) {
        unlink($textFile . '.tmp');
    }
}