sha is a simple program that hashes files. It uses the National Institute of Standards and Technology's Secure Hash Algorithm. It can use SHA-1, SHA-256, SHA-384, or SHA-512, which generate respectively, hashes of 160, 256, 384, or 512 bits. sha can be used in scripts to do, for example, file integrity checking.
You may want to perform a sanity check on sha before relying on it. A program called "shatest" is built along with sha. If you run shatest, it will display the results of running the various SHA algorithms on a set of known test vectors. If the resultant hash matches what is expected, "PASS" will be displayed. Otherwise it will display "FAIL."
