Using the MD5 Hash for Duplicate File Deletion

This function uses an MD5 hash to rapidly detect and delete duplicate files in a directory.

This function rapidly compares large numbers of files for identical content by computing the MD5 hash of each file and detecting duplicates. The probablility of two non-identical files having the same MD5 hash, even in a hypothetical directory containing as many as a million files, is exceedingly remote. Thus, since hashes rather than file contents are compared, the process of detecting duplicates is greatly accelerated.

You must have the file md5DLL.dll on your MATLAB path to use this function. The function is stored in the MATLAB Central File Exchange, file #3784, and was written by Hans-Peter Suter. The URL for the download site is:
http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=3784&objectType=file

This function is intended for MS Windows operating systems. This is because MATLAB requires on the order of 0.1 seconds to execute an operating system command to delete each file, but can rapidly create and run an operating system batch file to perform the file deletions much faster. Since I use MATLAB on a Windows PC, this function creates a batch file for that platform. Futhermore, the md5DLL.dll file is specific to Windows.