How do I determine my drive's file format?
To find out what type of file system the currently mounted drive is running use this command:
df -T
For more on the "df" tool you can visit the man page via:
man df
(press q to exit)
To find out, just run disk utility to find out the drive format type.
Use Disk Utility and click on the drive you are interested in. A block diagram will be displayed and labels will indicate the format type.