Introduction
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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.
Using sha is simple. Just pass the names of one or more files on
the command line.
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."
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