Getting the hash of a file

The Fingerprint of a File: md5_file()

The md5_file() function calculates the md5 hash of a given file (the fingerprint).

The md5 hash is a string with a 32-character hexadecimal number.

It is useful when you need to compare 2 versions of the same file. For example, it is useful for large files downloaded from the internet just to check if the download file is corrupted and/or matches with the original file.

Or it is useful to track if a file was changed. If two md5 hashes are equal, it means that the two files have the identical content.

echo md5_file(__FILE__);
// 0cd9c44d2e3a87fc1217c02f69f78fa6