NAME blockdev - call block device ioctls from the command line

SYNOPSIS blockdev [options] commands devices blockdev --report [devices]

DESCRIPTION The utility blockdev allows one to call block device ioctls from the command line.

OPTIONS -V Print version and exit.

-q Be quiet.

-v Be verbose.

--report Print a report for devices. Note that the partition StartSec is in 512-byte sectors.

COMMANDS --setro Set read-only.

--setrw Set read-write.

--getro Get read-only. Print 1 if the device is read-only, 0 otherwise.

--getss Print sectorsize in bytes - usually 512.

--getbsz Print blocksize in bytes.

--setbsz N Set blocksize to N bytes. Note that the block size is specific to the current file descriptor opening the block device, so the change of block size only persists for as long as blockdev has the device open, and is lost once blockdev exits.

--getsize Print device size in sectors (BLKGETSIZE). Deprecated in favor of the --getsz option.

--getsize64 Print device size in bytes (BLKGETSIZE64)

--getsz Get size in 512-byte sectors (BLKGETSIZE64 / 512).

--setra N Set readahead to N 512-byte sectors.

--getra Print readahead (in 512-byte sectors).

--setfra N Set filesystem readahead (same like --setra on 2.6 kernels).

--getfra Get filesystem readahead.

--flushbufs Flush buffers.

--rereadpt Reread partition table.

AUTHOR blockdev was written by Andries E. Brouwer.

AVAILABILITY The blockdev command is part of the util-linux-ng package and is avail- able from

Jun 2007 BLOCKDEV(8)