- In Unix-like operating systems, a device file or special file is an interface to a device driver that appears in a file system as if it were an ordinary file.
On Linux they are in the
/dev directory, according to the Filesystem Hierarchy Standard.
On Arch Linux the device nodes are managed by udev.
Block devices provide buffered access to hardware devices and allow reading and writing blocks of any size and alignment.
The beginning of the device name specifies the type of block device. Most modern storage devices (e.g. hard disks, SSDs and USB flash drives) are recognised as SCSI disks (
sd). The type is followed by a lower-case letter starting from
a for the first device (
b for the second device (
sdb), and so on. Existing partitions on each device will be listed with a number starting from
1 for the first partition (
2 for the second (
sda2), and so on. Other common block device types include for example
mmcblk for memory cards and
nvme for NVMe devices.
See also Persistent block device naming.
Thepackage provides the utility which lists block devices, for example:
$ lsblk -f
NAME FSTYPE LABEL UUID MOUNTPOINT sda ├─sda1 vfat C4DA-2C4D /boot ├─sda2 swap 5b1564b2-2e2c-452c-bcfa-d1f572ae99f2 [SWAP] └─sda3 ext4 56adc99b-a61e-46af-aab7-a6d07e504652 /
In the example above, only one device is available (
sda), and that device has three partitions (
sda3), each with a different file system.
wipefs can list or erase file system, RAID or partition-table signatures (magic strings) from the specified device to make the signatures invisible for . It does not erase the file systems themselves nor any other data from the device.
Seefor more information.
For example, to erase all signatures from the device
/dev/sdb and create a signature backup
~/wipefs-sdb-offset.bak file for each signature:
# wipefs --all --backup /dev/sdb
Device nodes that do not have a physical device.