Inspecting file systems and block devices

File system information

sudo dumpe2fs /dev/<device>

Or for size information:

sudo dumpe2fs /dev/<device> | grep size

Physical blocks of a file

sudo PAGER=cat debugfs -R 'stat <file>' /dev/<device>

Notes: -<file> must be relative to the file system. --R is used to give a direct command. Omit -R '...' to enter interactive mode. -PAGER=cat ensures that no pager (as less) is used.

Check man debugfs for additional commands.