Determining which filesystems are present on mounted or unmounted volumes

9 May 2026

lsblk

lsblk -f will show you a list of devices, partitions, their corresponding filesystem type, available/used space, and mountpoints.

$ lsblk -f
NAME FSTYPE FSVER LABEL  UUID                                 FSAVAIL FSUSE% MOUNTPOINTS
sda
├─sda1
│
├─sda2
│    vfat   FAT16        2205-C8D2                               191M     4% /boot/efi
├─sda3
│    xfs                 6df325af-1779-4165-a6cd-78fe83c18aab    745M    22% /boot
└─sda4
     xfs                 99bf1bf0-97c8-472e-9e64-fc4fee387b2b    7.4G    15% /
sr0  iso966 Jolie cidata 2026-04-09-17-29-07-00

file

file --special-files --dereference (-sL) will give you information on a partition/LV’s filesystem or the MBR on a disk. Can be used on mounted or unmounted partitions.

Here’s what this looks like with.. something.. left behind by a W11 24H2 install:

$ sudo file -sL /dev/sda
/dev/sda: DOS/MBR boot sector MS-MBR Windows 7 english at offset 0x163 "Invalid partition table" at offset 0x17b "Error loading operating system" at offset 0x19a "Missing operating system"; partition 1 : ID=0xee, start-CHS (0x0,0,2), end-CHS (0x30,254,63), startsector 1, 4294967295 sectors

Here’s what this looks like with a protective MBR (note the single partition with type 0xee):

$ sudo file -sL /dev/nvme0n1
/dev/nvme0n1: DOS/MBR boot sector; partition 1 : ID=0xee, start-CHS (0x0,0,2), end-CHS (0x3ff,255,63), startsector 1, 2000409263 sectors, extended partition table (last)

Here are three types of partitions:

an EFI boot partition (vfat)
an XFS partition (/boot)
a LVM partition (PV)

$ sudo file -sL /dev/nvme0n1p1
/dev/nvme0n1p1: DOS/MBR boot sector, code offset 0x3c+2, OEM-ID "mkfs.fat", sectors/cluster 4, reserved sectors 4, root entries 512, Media descriptor 0xf8, sectors/FAT 128, sectors/track 32, heads 64, hidden sectors 2048, sectors 131072 (volumes > 32 MB), reserved 0x1, serial number 0x14409030, unlabeled, FAT (16 bit)

$ sudo file -sL /dev/nvme0n1p2
/dev/nvme0n1p2: SGI XFS filesystem data (blksz 4096, inosz 512, v2 dirs)

$ sudo file -sL /dev/nvme0n1p3
/dev/nvme0n1p3: LVM2 PV (Linux Logical Volume Manager), UUID: 4j6gw3-qqmW-kUme-ggMY-gknT-AOEs-8luOM9, size: 137447342080

Here’s what a LV looks like:

$ sudo file -sL /dev/800g4/var
/dev/800g4/var: Linux rev 1.0 ext4 filesystem data, UUID=e2dc8883-6158-46c7-870d-74bff4aedffd (needs journal recovery) (extents) (64bit) (large files) (huge files)

Finally, here’s what a Windows install looks like.

sda1 is an EFI partition
sda2 is a MSR partition
sda3 is a NTFS data partition
sda4 is a Windows Recovery Environment partition

$ sudo file -sL /dev/sda1
/dev/sda1: DOS/MBR boot sector, code offset 0x58+2, OEM-ID "MSDOS5.0", sectors/cluster 8, reserved sectors 7166, Media descriptor 0xf8, sectors/track 63, heads 255, hidden sectors 2048, sectors 532480 (volumes > 32 MB), FAT (32 bit), sectors/FAT 513, reserved 0x1, serial number 0x72eb3a0d, unlabeled

$ sudo file -sL /dev/sda2
/dev/sda2: data

$ sudo file -sL /dev/sda3
/dev/sda3: DOS/MBR boot sector, code offset 0x52+2, OEM-ID "NTFS    ", sectors/cluster 8, Media descriptor 0xf8, sectors/track 63, heads 255, hidden sectors 567296, dos < 4.0 BootSector (0x80), FAT (1Y bit by descriptor); NTFS, sectors/track 63, sectors 1951721471, $MFT start cluster 786432, $MFTMirror start cluster 2, bytes/RecordSegment 2^(-1*246), clusters/index block 1, serial number 0d040ed3d40ed2ac4; contains bootstrap BOOTMGR

$ sudo file -sL /dev/sda4
/dev/sda4: DOS/MBR boot sector, code offset 0x52+2, OEM-ID "NTFS    ", sectors/cluster 8, Media descriptor 0xf8, sectors/track 63, heads 255, hidden sectors 1952288768, dos < 4.0 BootSector (0x80), FAT (1Y bit by descriptor); NTFS, sectors/track 63, sectors 1232895, $MFT start cluster 51370, $MFTMirror start cluster 2, bytes/RecordSegment 2^(-1*246), clusters/index block 1, serial number 0a6e0c069e0c04173; contains bootstrap BOOTMGR

blkid

Alternatively, you could look at the ’type’ fields in the output of blkid.

$ sudo blkid
/dev/mapper/800g4-var: UUID="e2dc8883-6158-46c7-870d-74bff4aedffd" TYPE="ext4"
/dev/nvme0n1p3: UUID="4j6gw3-qqmW-kUme-ggMY-gknT-AOEs-8luOM9" TYPE="LVM2_member" PARTUUID="967c90be-76ab-4da1-88b4-c209e6eb84d6"
/dev/nvme0n1p1: SEC_TYPE="msdos" UUID="1440-9030" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="6186fdfa-530a-4f6c-b0a7-bbc238b03f2e"
/dev/nvme0n1p2: UUID="71d3600d-5a34-456a-bea1-01d776726d2b" TYPE="xfs" PARTUUID="8cfb4928-91ab-4795-b334-a776a147916a"
/dev/mapper/800g4-root: UUID="38484eee-b428-4b99-9629-53d16b2fb5bb" TYPE="ext4"
/dev/sda4: UUID="A6E0C069E0C04173" TYPE="ntfs" PARTUUID="2a61485a-e223-41d2-8bfa-514bbf60d684"
/dev/sda3: UUID="D040ED3D40ED2AC4" TYPE="ntfs" PARTLABEL="Basic data partition" PARTUUID="035dab53-9703-4196-a1e1-d1dbc2c15478"
/dev/sda1: UUID="72EB-3A0D" TYPE="vfat" PARTLABEL="EFI system partition" PARTUUID="91c3fe2c-5640-41ad-9a35-cfc4525baa39"
/dev/sda2: PARTLABEL="Microsoft reserved partition" PARTUUID="265af130-5fe5-4bdc-a673-c90609c29bb3"

It’ll see most things without elevation, assuming the cache file (/run/blkid/blkid.tab) has been updated. Run as root if you want to force a check.

$ blkid
/dev/mapper/800g4-var: UUID="e2dc8883-6158-46c7-870d-74bff4aedffd" TYPE="ext4"
/dev/nvme0n1p3: UUID="4j6gw3-qqmW-kUme-ggMY-gknT-AOEs-8luOM9" TYPE="LVM2_member" PARTUUID="967c90be-76ab-4da1-88b4-c209e6eb84d6"
/dev/nvme0n1p1: SEC_TYPE="msdos" UUID="1440-9030" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="6186fdfa-530a-4f6c-b0a7-bbc238b03f2e"
/dev/nvme0n1p2: UUID="71d3600d-5a34-456a-bea1-01d776726d2b" TYPE="xfs" PARTUUID="8cfb4928-91ab-4795-b334-a776a147916a"
/dev/mapper/800g4-root: UUID="38484eee-b428-4b99-9629-53d16b2fb5bb" TYPE="ext4"
/dev/sda4: UUID="A6E0C069E0C04173" TYPE="ntfs" PARTUUID="2a61485a-e223-41d2-8bfa-514bbf60d684"
/dev/sda3: UUID="D040ED3D40ED2AC4" TYPE="ntfs" PARTLABEL="Basic data partition" PARTUUID="035dab53-9703-4196-a1e1-d1dbc2c15478"
/dev/sda1: UUID="72EB-3A0D" TYPE="vfat" PARTLABEL="EFI system partition" PARTUUID="91c3fe2c-5640-41ad-9a35-cfc4525baa39"

df

df -T will show you the type of mounted filesystems. Combine this with -h for a nicely formatted (size-wise) output.

$ df -T
Filesystem             Type     1K-blocks    Used Available Use% Mounted on
devtmpfs               devtmpfs      4096       0      4096   0% /dev
tmpfs                  tmpfs      7940048       0   7940048   0% /dev/shm
tmpfs                  tmpfs      3176020    9076   3166944   1% /run
efivarfs               efivarfs       150      76        70  53% /sys/firmware/efi/efivars
/dev/mapper/800g4-root ext4      65478188 1370608  60735756   3% /
/dev/mapper/800g4-var  ext4      65478188  149748  61956616   1% /var
/dev/nvme0n1p2         xfs        5177344  357452   4819892   7% /boot
/dev/nvme0n1p1         vfat         65390    7198     58192  12% /boot/efi
tmpfs                  tmpfs      1588008       0   1588008   0% /run/user/1000

Another example from a PVE machine:

$ df -T
Filesystem                                  Type     1K-blocks     Used Available Use% Mounted on
udev                                        devtmpfs  32764056        0  32764056   0% /dev
tmpfs                                       tmpfs      6561580     6464   6555116   1% /run
/dev/mapper/pve-root                        ext4      38593904 22692252  13908948  62% /
tmpfs                                       tmpfs     32807888    55008  32752880   1% /dev/shm
efivarfs                                    efivarfs       150       97        49  67% /sys/firmware/efi/efivars
tmpfs                                       tmpfs         5120        0      5120   0% /run/lock
tmpfs                                       tmpfs         1024        0      1024   0% /run/credentials/systemd-journald.service
tmpfs                                       tmpfs     32807888        0  32807888   0% /tmp
/dev/sda2                                   vfat       1046508     8976   1037532   1% /boot/efi
/dev/fuse                                   fuse        131072       76    130996   1% /etc/pve
tmpfs                                       tmpfs         1024        0      1024   0% /run/credentials/getty@tty1.service
169.254.50.10,169.254.50.11,169.254.50.12:/ ceph     439390208 19681280 419708928   5% /mnt/pve/cephfs
tmpfs                                       tmpfs      6561576        4   6561572   1% /run/user/1000

fsck

fsck -N (the dry run switch) will list detected filesystems (in a way, via the fsck utility for the filesystem type). Not sure if it would be my first choice to do this.

Don’t try to fsck a live filesystem if you don’t know exactly what you’re doing. Always run with the -N switch if you’re trying to do this. Most fsck utilities (EXT4, XFS) will warn you and/or refuse to run on a mounted partition, but if you do force a run it’ll likely lead to corruption.

$ fsck -N
fsck from util-linux 2.37.4
[/usr/sbin/fsck.ext4 (1) -- /] fsck.ext4 /dev/mapper/800g4-root
[/usr/sbin/fsck.vfat (1) -- /boot/efi] fsck.vfat /dev/nvme0n1p1
[/usr/sbin/fsck.ext4 (1) -- /var] fsck.ext4 /dev/mapper/800g4-var

parted

parted /device/path print will return the disk’s size, sector size, partition table type, and any contained partitions’ sizes, labels, flags, and filesystems. It won’t be able to get you information about some filesystems or mapper devices. This works for mounted and unmounted partitions.

$ sudo parted /dev/sda print
Model: ATA WDC WDS100T2B0A (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                          Flags
 1      1049kB  274MB   273MB   fat32        EFI system partition          boot, esp
 2      274MB   290MB   16.8MB               Microsoft reserved partition  msftres
 3      290MB   1000GB  999GB   ntfs         Basic data partition          msftdata
 4      1000GB  1000GB  631MB   ntfs                                       hidden, diag

parted /dev/path print all will enumerate all disks in the system.

$ sudo parted /dev/sda print all
Model: ATA WDC WDS100T2B0A (scsi)
Disk /dev/sda: 1000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                          Flags
 1      1049kB  274MB   273MB   fat32        EFI system partition          boot, esp
 2      274MB   290MB   16.8MB               Microsoft reserved partition  msftres
 3      290MB   1000GB  999GB   ntfs         Basic data partition          msftdata
 4      1000GB  1000GB  631MB   ntfs                                       hidden, diag


Model: INTEL SSDPEKNU010TZ (nvme)
Disk /dev/nvme0n1: 1024GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                  Flags
 1      1049kB  68.2MB  67.1MB  fat16        EFI System Partition  boot, esp
 2      68.2MB  5437MB  5369MB  xfs
 3      5437MB  143GB   137GB                                      lvm

Note how it can’t figure out this Joliet cidata file (/dev/sr0):

$ sudo parted /dev/sda print all
Model: QEMU QEMU HARDDISK (scsi)
Disk /dev/sda: 10.7GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name                  Flags
 1      1049kB  2097kB  1049kB               biosboot              bios_grub
 2      2097kB  212MB   210MB   fat16        EFI System Partition  boot, esp
 3      212MB   1286MB  1074MB  xfs          boot
 4      1286MB  10.7GB  9451MB  xfs          root


Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0 has been opened read-only.
Error: /dev/sr0: unrecognised disk label
Model: QEMU QEMU DVD-ROM (scsi)
Disk /dev/sr0: 4194kB
Sector size (logical/physical): 2048B/2048B
Partition Table: unknown
Disk Flags:

Or this Ceph OSD (/dev/sdb):

$ sudo parted /dev/sda print all
Model: ATA INTEL SSDSC2BB12 (scsi)
Disk /dev/sda: 120GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system  Name  Flags
 1      17.4kB  1049kB  1031kB                     bios_grub
 2      1049kB  1075MB  1074MB  fat32              boot, esp
 3      1075MB  120GB   119GB                      lvm


Error: /dev/sdb: unrecognised disk label
Model: ATA INTEL SSDSC2BB48 (scsi)
Disk /dev/sdb: 480GB
Sector size (logical/physical): 512B/4096B
Partition Table: unknown
Disk Flags:

Honorary mention - fdisk

Probably the first thing to come to mind. Good old fdisk. Doesn’t quite do the trick - you can’t see what filesystem is on a disk at first glance, just the partition type (e.g., Linux filesystem).

Quick peruse of the manpage and Google leads me to believe this will not look at filesystem metadata at all.

$ sudo fdisk -l
Disk /dev/nvme0n1: 953.87 GiB, 1024209543168 bytes, 2000409264 sectors
Disk model: INTEL SSDPEKNU010TZ
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 5A164C26-DF9A-41B7-8411-FB5F0F40AB17

Device            Start       End   Sectors  Size Type
/dev/nvme0n1p1     2048    133119    131072   64M EFI System
/dev/nvme0n1p2   133120  10618879  10485760    5G Linux filesystem
/dev/nvme0n1p3 10618880 279070719 268451840  128G Linux LVM


Disk /dev/sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: WDC  WDS100T2B0A
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 794F080D-0A9B-432C-9BD8-2EA0AE01103A

Device          Start        End    Sectors   Size Type
/dev/sda1        2048     534527     532480   260M EFI System
/dev/sda2      534528     567295      32768    16M Microsoft reserved
/dev/sda3      567296 1952288767 1951721472 930.7G Microsoft basic data
/dev/sda4  1952288768 1953521663    1232896   602M Windows recovery environment


Disk /dev/mapper/800g4-root: 64 GiB, 68719476736 bytes, 134217728 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/800g4-var: 64 GiB, 68719476736 bytes, 134217728 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes