Q: How do I find the MD5 Checksum for a file

Context

• An md5 checksum is a crytographic hash of a file that is unique. They are often used to verify that the file you downloaded is the one that you are supposed to have and that someone (or some problem in the download) didn't change the file.

Answer

Mac OS X

1. Launch Terminal
2. run command _md5 <filename>_

   bob$ md5 /Users/bob/Desktop/downloadedfile.dmg
   MD5 (Users/bob/Desktop/downloadedfile.dmg) = d9a042dc0da64e8a3d14eeb7cba5ae8f

Windows

1. Download FCIV from Microsoft
   http://support.microsoft.com/kb/841290 (yes it is old, but it works)
2. Install FCIV (File Checksum Integrity Verifier)
   1. You will have to the location of FCIV to your system path or install it to a location already in your path or use the full path name to run the command.
3. Launch CMD prompt (Start Run cmd)
   1. fciv.exe /path/to/downloadedfile.zip -md5

      //
      // File Checksum Integrity Verifier version 2.05.
      //
      eb06fb60aac2d9836c5fbbddb26f099a downloadedfile.zip

   2. Use the -sha1 to get a SHA1 hash instead.

The md5 checksum of the same file on any machine should be identical.