file

# show partition information
file -sL

# follow symlinks
-L

# read special files, such as block or character devices, and attempt to identify their content based on the data contained within them. It's often used for analyzing disk partitions or raw disk images.
-s

# check mime type
--mime-type

# find the mimetype of a file
file -i filename

# to see the existing partition on a disk
file -s /dev/sdb1

# Use the file -s command to get information about a specific device, such as its file system type. If the output shows simply data, as in the following example output, there is no file system on the device
sudo file -s /dev/sda