Today I downloaded Valgrind and wanted to verify the download's integrity. Valgrind provides an MD5 digest with each release that you can check against.
I used OpenSSL's
md5 on OSX:
$ md5 valgrind-3.11.0.tar.bz2 MD5 (valgrind-3.11.0.tar.bz2) = 4ea62074da73ae82e0162d6550d3f129
This matches the digest on the Valgrind website, verifying the download.
md5sum would be a comparable Linux program.