SHA

SHA-0 (Secure Hash Algorithm) was a proposal by the U.S. government that was replaced by SHA-1 in FIPS 180-1. SHA-1 addresses the weakness found in SHA-0 by adding an additional circular shift operation. SHA-1 has a reported weakness as far as hash collisions are concerned and awareness should be raised if you are implementing it.

If you have the sha1 application installed, you can make use of the command like so:

$ sha1 /etc/passwd
SHA1 (/etc/passwd) = c7ae5b7306797d9f1f5fba85683cdd36ba8d1a08