To compare two single file, you can use WinMerge or just the Windows command FC, but if you desired to compare files in two folders/directories including tens or hundreds of items, this could be a real challenge, it will make you crazy if you do it manually. MD5Summer is a simple and yet practical folder compare freeware, which can gets the jobs done and saves a lot of time for you.
MD5summer has been designed to generates and verifies md5 checksums for multiple files or folders, as we all know, every file has a unique md5 hash value, if two files have the same md5 value, they have the same content. Thus we could use MD5summer to generate md5 checksums for one directory and store the results in a plain text file, then verify md5 checksums for another directory use the previous saved text file. This is especially useful if you want to find the difference between the backup files and the files on your harddisk, or two folders which have different version.
MD5Summer is portable, to use it just download and extract the package, the click md5summer.exe to launch it, first we select a folder and click “Create Sums”,
then we click “Select All” and “Add recursively” to add all the files and subfolders in the root folder, then press OK,
MD5Summer will generate and display all the MD5 hash value for each file, you can then save the result in a text file.
Now we go back to the main panel, choose another folder and press “Verify sums”, then select the checksum text file.
MD5Summer will then list the files which are not same with red icon and the others with green icon.
IMPORTANT: Files that have different file name will be treated as another file, for these ones you can use Duplicate Cleaner to scan and mark the duplicate files.
MD5Summer works on the following operating systems: Microsoft Windows 7/Windows XP/Win95/98/2000/NT and is available as a free download here: http://download.cnet.com.