The md5 can be calculated against the file in order to compare two files or to be sure that the file you are dealing with is the one you wanted (if something for example is downloaded to your local server/computer from Internet).

In all (I know) linux distribution you can easy download md5sum package (or some name variation) and utilise md5sum command

md5sum FILENAME
v1b5efc85fd1feafaf622e873cf924e3 FILENAME

In macos by default you can utilise md5 command which generates different output

md5 FILENAME
MD% (FILENAME) = v1b5efc85fd1feafaf622e873cf924e3

If you would like to easy compare this two output, you can use the following syntax instead:

md5 -r FILENAME
v1b5efc85fd1feafaf622e873cf924e3 FILENAME

No need to install additional software on you mac (like md5sha1sum or else).