md5_file Calculates the md5 hash of a given filename stringmd5_file stringfilename boolraw_output Calculates the MD5 hash of the specified filename using the RSA Data Security, Inc. MD5 Message-Digest Algorithm, and returns that hash. The hash is a 32-character hexadecimal number. If the optional raw_output is set to &true;, then the md5 digest is instead returned in raw binary format with a length of 16. The optional raw_output parameter was added in PHP 5.0.0 and defaults to &false; This function has the same purpose of the command line utility md5sum. See also md5, crc32, and sha1_file.