Using md5sum

Often I see a md5sum file when I download a large file. How can I check if I've downloaded the large file correctly?
(i) first, paste the md5sum information into a file called 'MD5SUM':
eg.

a477b9935efe786a16e7ccb13527b68d  prot.accession2taxid.gz

(ii) then, run:

% md5sum -c MD5SUMS

Hopefully, this will say all is fine:

prot.accession2taxid.gz: OK