How do I identify the file system of a drive in Mac OS?
diskutil(8) with the
info predicate will give you information about a disk or partition.
Highlight the volume in finder (note, that it must be the root of the volume), and hit cmd + i. The info dialog that appears shows you the filesystem type against the
Terminal.app also works and has way less noise when compared to
diskutil info -all.
Unless you're wedded to doing it from the command line, use Disk Utility and it's "Info" button.