blockdev

Report all devices

$ sudo blockdev --report

$ sudo blockdev --report /dev/sda1

$ sudo blockdev --getsz /dev/sda1

$ sudo blockdev --setro /dev/sda1

$ sudo blockdev --setrw /dev/sda1

$ sudo blockdev --flushbufs /dev/sda1

$ sudo blockdev --getpbsz /dev/sda1

$ sudo blockdev --setra 128 /dev/sda1

blockdev [OPTIONS] device...

blockdev queries and manipulates block device properties from the command line. It can report device sizes, set read-only/read-write modes, flush buffers, and configure performance parameters like read-ahead.

--report

Print a report for specified devices or all devices

Get size in 512-byte sectors

Get size in bytes

Get physical block size

Get logical block size

Set device to read-only

Set device to read-write

Flush buffers

Set read-ahead value in 512-byte sectors

Get current read-ahead value

Requires root privileges. Setting a device read-only while mounted may cause issues. Changes to read-ahead affect I/O performance and may not be beneficial for all workloads.

blockdev is part of the util-linux package, providing low-level block device management on Linux systems.

lsblk(8), blkid(8), fdisk(8)