1) MD5SUM for Linux Most Linux already comes with md5sum tool. Simply type md5sum -c MD5SUM to verify if the package is valid. ex) $ md5sum -c MD5SUM $ openwebmail-2.10-1.i386.rpm: OK man md5sum for more info 2) MD5SUM for Windows Installation ============ Windows 95/98/Me: Download md5sum.exe to c:\windows\command Windows NT/2000: Download md5sum.exe to your c:\winnt\system32 Checking ======== Open an MS-DOS window and go to the directory of the show you want to check. When you are in that directory, type: md5sum -c [filename].md5 OR md5sum -c MD5SUM Creating ======== Open an MS-DOS window and go to the directory of the show you want to create an .md5 file for. When you are in that directory, type: md5sum * > [filename].md5 OR md5sum * > MD5SUM