| FSTYP(8) | System Manager's Manual | FSTYP(8) | 
fstyp —
| fstyp | [ -lsu] special | 
fstyp utility is used to determine the file system
  type on a given device. It can recognize ISO-9660, exFAT, Ext2, FAT, NTFS,
  UFS, HAMMER, and HAMMER2 file systems. When the -u
  flag is specified, fstyp also recognizes certain
  additional metadata formats that cannot be handled using
  mount(8), such as ZFS pools.
The file system name is printed to the standard output as, respectively:
Note that a HAMMER file system consisting of more than one volume requires a path in blkdevs format.
Because fstyp is built specifically to
    detect file system types, it differs from
    file(1) in several ways. The
    output is machine-parsable, file system labels are supported, and it does
    not try to recognize any file format other than file systems.
These options are available:
-l-sfstyp only works on
      regular files and disk-like device nodes. Trying to read other file types
      might have unexpected consequences or hang indefinitely.-ufstyp utility exits 0 on success, and >0 if an
  error occurs or the file system type is not recognized.
fstyp command appeared in FreeBSD
  10.2. The fstyp command appeared in
  DragonFly 4.5. The fstyp
  command appeared in NetBSD 9.0.
fstyp utility was developed by
  Edward Tomasz Napierala
  <trasz@FreeBSD.org>
  under sponsorship from the FreeBSD Foundation. ZFS and
  GELI support was added by Allan Jude
  <allanjude@FreeBSD.org>.
The fstyp utility was ported to
    DragonFly and NetBSD by
    Tomohiro Kusumi
    <tkusumi@netbsd.org>.
| January 1, 2020 | NetBSD 10.0 |