Mac OS X: how to generate md5 sha1 sha256 checksums from command line

Running shasum is often the quickest way to compute SHA message digests. The user simply feeds data to the script through files or standard input, and then collects the results from standard output.

If you want more info of the shasum check here the man page

Calculate MD5 checksum:

md5 /tmp/ubuntu.iso

Calculate SHA-1 checksum:

shasum -a 1 ubuntu.iso

Calculate SHA-256 checksum:

shasum -a 256 ubuntu.iso