# lsblk — List Block Devices as a Tree > Practical guide to lsblk — show disks, partitions and mount points as a readable tree and pick the right device before running dd, fdisk or mount. Source: https://www.jpkc.com/db/en/cheatsheets/shell-system/lsblk/ lsblk lists every block device on your system – hard disks, SSDs, partitions, loop devices and USB sticks – as a readable tree with name, size, type and mount point. It reads its information straight from the kernel (sysfs/udev) and is a pure read-only command: it changes nothing and is safe to run as often as you like. That makes lsblk the ideal sanity check before you operate on a device with `dd`, `fdisk` or `mount` – you confirm exactly which `/dev/…` you are dealing with and avoid grabbing the wrong disk by accident. ## Basic Usage `lsblk` — List all block devices in tree format. ```bash lsblk ``` `lsblk -a` — Show all devices including empty ones. ```bash lsblk -a ``` `lsblk ` — Show info for a specific device. ```bash lsblk /dev/sda ``` `lsblk -l` — List format (flat, no tree). ```bash lsblk -l ``` ## Output Columns `lsblk -f` — Show filesystem type, label, UUID, and mount point. ```bash lsblk -f ``` `lsblk -o ` — Show specific columns. ```bash lsblk -o NAME,SIZE,FSTYPE,MOUNTPOINT,UUID ``` `lsblk -o NAME,SIZE,TYPE,TRAN,MODEL` — Show device model and transport type. ```bash lsblk -o NAME,SIZE,TYPE,TRAN,MODEL ``` `lsblk -O` — Show all available columns. ```bash lsblk -O ``` `lsblk --help` — Show help, including the list of all available column names. ```bash lsblk --help ``` ## Output Formats `lsblk -J` — Output in JSON format. ```bash lsblk -J ``` `lsblk -P` — Output in key=value pairs format. ```bash lsblk -P ``` `lsblk -r` — Raw output (for scripting). ```bash lsblk -r -o NAME,SIZE,MOUNTPOINT ``` `lsblk -b` — Show sizes in bytes instead of human-readable. ```bash lsblk -b ``` ## Filtering `lsblk -d` — Show only whole disks (no partitions). ```bash lsblk -d ``` `lsblk -n` — Suppress the header line. ```bash lsblk -n -o NAME,SIZE ``` `lsblk -e ` — Exclude devices by major number (7=loop). ```bash lsblk -e 7 ``` `lsblk -I ` — Include only devices with a specific major number (8=SCSI/SATA). ```bash lsblk -I 8 ``` ## Common Patterns `lsblk -d -o NAME,SIZE,MODEL,TRAN` — List physical disks with model and interface type. ```bash lsblk -d -o NAME,SIZE,MODEL,TRAN ``` `lsblk -f -o NAME,FSTYPE,SIZE,MOUNTPOINT,FSUSE%` — Show filesystem usage per partition. ```bash lsblk -f -o NAME,FSTYPE,SIZE,MOUNTPOINT,FSUSE% ``` `lsblk -o NAME,UUID -n -l | grep -v '^$'` — List all partition UUIDs (for fstab). ```bash lsblk -o NAME,UUID -n -l | grep -v '^$' ``` `lsblk -S` — Show SCSI/SATA device information. ```bash lsblk -S ``` ## Conclusion lsblk is one of those commands worth picking up early: a single call gives you a clear overview of every disk, its partitions and where they are mounted. Day to day you mostly need plain `lsblk` for the tree and `lsblk -f` to see filesystems, labels and UUIDs; with `-o` and `-J` you tailor the output for reports or scripts. Its biggest value is as a safe sanity check: always confirm with lsblk which `/dev/…` device you are looking at before you touch it with `dd`, `fdisk` or `mount`. lsblk itself writes nothing and does no harm – the danger only arises when you hand the wrong device to a destructive command. ## Further Reading - [lsblk(8) — man page](https://man7.org/linux/man-pages/man8/lsblk.8.html) – complete reference of all options and output columns - [Arch Wiki: Persistent block device naming](https://wiki.archlinux.org/title/Persistent_block_device_naming) – how UUIDs and labels from lsblk map to stable device names in fstab ## Related Commands - [fdisk](https://www.jpkc.com/db/en/cheatsheets/shell-system/fdisk/) – view and edit disk partition tables - [mount](https://www.jpkc.com/db/en/cheatsheets/shell-system/mount/) – attach filesystems to the directory tree - [df-du](https://www.jpkc.com/db/en/cheatsheets/shell-system/df-du/) – check used and free disk space