xdiff_file_diff

Make unified diff of two files (PECL xdiff:0.2-1.4)
bool xdiff_file_diff ( string file1, string file2, string dest [, int context [, bool minimal]] )

Makes a diff of two files and stores the result in a file.

file1
file2
dest: Path of the resulting file.
context: Indicates how many lines of context you want to include in diff result.
minimal: Set this parameter to TRUE if you want to minimalize size of diff (can take a long time). Resulting file is human-readable.

Returns TRUE on success or FALSE on failure.

The following code makes unified diff of two php files.

<?php

$old_version = 'my_script.php';
$new_version = 'my_new_script.php';

xdiff_file_diff($old_version, $new_version, 'my_script.diff', 2);
?>

Note:

This function doesn't work well with binary files. To make diff of binary files use xdiff_file_diff_binary().