How to verify an MD5 checksum on Mac OS X
MessageDigest5 (MD5) checksums provide a way for you to confirm the integrity of files you download or copy. The MD5 algorithm takes a file as input and outputs a highly unique fingerprint message digest. To confirm file integrity, use an MD5 utility on your computer to calculate your own MD5 message digest for files downloaded from a web site or copied from a directory on a computer. If your calculated MD5 checksum matches the original, you can be assured your file is intact and probably not “corrupt”. MD5 utilities are available for Windows and Linux and Mac. Most Linux installations provide an md5sum command for calculating MD5 message digests. Here are the simple steps on a Mac system:
- Open a Terminal window (navigate to /Applications/Utilities/Terminal.app)
- Type: “md5 ” (md5 followed by a space).
- Drag the downloaded file you want to check from the Finder into the Terminal window.
- Click in the Terminal window and press the Return key to run the command.
- Compare this locally-generated checksum to the source checksum. If it’s a match, the files are a match!
