man mount
:
If no -t
option is given, or if the auto type is specified, mount
will try to guess the desired type. Mount
uses the blkid
library for guessing the filesystem type; if that does not turn up anything that looks familiar,
mount will try to read the file /etc/filesystems
, or, if that does not exist, /proc/filesystems
. All of the
filesystem types listed there will be tried, except for those that are labeled "nodev" (e.g., devpts, proc and
nfs). If /etc/filesystems ends
in a line with a single * only, mount will read /proc/filesystems
afterwards.
# mount -V
mount from util-linux-ng 2.17.2 (with libblkid and selinux support)
Besides the blk_id
:
# blkid -o value -s TYPE /dev/sdb1
ext4
there are some other ways to determine the filesystem of an unmounted partition:
# file -s /dev/sdb1
/dev/sdb1: Linux rev 1.0 ext4 filesystem data (extents) (large files) (huge files)
# fsck -N /dev/sdb1
fsck from util-linux-ng 2.17.2
[/sbin/fsck.ext4 (1) -- /dev/sdb1] fsck.ext4 /dev/sdb1
# parted /dev/sdb1 print
Model: Unknown (unknown)
Disk /dev/sdb1: 107GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Number Start End Size File system Flags
1 0.00B 107GB 107GB ext4