How do you find out which filesystem a partition holds, and its UUID?

lsblk -f shows the tree of devices with their filesystem type, UUID, and mount point; blkid does the same for one device.

Before you mount or format anything you need to know what's already there — wiping the wrong partition is unrecoverable. Two tools answer this:

• lsblk ("list block devices") draws the whole device tree, showing how disks, partitions, and LVM volumes nest. Add -f for filesystem info (type, UUID, mountpoint) and -p for full /dev/... paths.
• blkid prints the UUID and filesystem type of a specific device.

lsblk -fp                  # full-path tree with FS type + UUID + mountpoint
blkid /dev/sda1            # UUID + TYPE for one device

Example lsblk -fp output, showing an LVM stack:

NAME                       FSTYPE  UUID          MOUNTPOINT
/dev/sda
├─/dev/sda1                ext4    abc123-...    /boot
└─/dev/sda2                LVM2    def456-...
  └─/dev/mapper/vg01-lv01  xfs     789ghi-...    /data

Why the UUID matters: the device name (/dev/sda1) is just a position label that can shift between reboots, but the UUID is baked into the filesystem when it's created and never changes. That's why /etc/fstab references UUIDs, and why you run lsblk -fp to grab the right one before editing fstab.

Go deeper:

• lsblk(8) man page — lsblk, including -f (filesystem info) and -p (full path).