blockdev(8)

NAME

   blockdev - call block device ioctls from the command line

SYNOPSIS

   blockdev [-q] [-v] command [command...] device [device...]
   blockdev --report [device...]

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 the specified device. It is possible to  give
          multiple  devices. If none is given, all devices which appear in
          /proc/partitions are shown. Note that the partition StartSec  is
          in 512-byte sectors.

COMMANDS

   It is possible to give multiple devices and multiple commands.

   --flushbufs
          Flush buffers.

   --getalignoff
          Get alignment offset.

   --getbsz
          Print blocksize in bytes.

   --getdiscardzeroes
          Get discard zeroes support status.

   --getfra
          Get filesystem readahead in 512-byte sectors.

   --getiomin
          Get minimum I/O size.

   --getioopt
          Get optimal I/O size.

   --getmaxsect
          Get max sectors per request

   --getpbsz
          Get physical block (sector) size.

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

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

   --getsize64
          Print device size in bytes.

   --getsize
          Print  device  size (32-bit!) in sectors. Deprecated in favor of
          the --getsz option.

   --getss
          Print sector size in bytes -- usually 512.

   --getsz
          Get size in 512-byte sectors.

   --rereadpt
          Reread partition table

   --setbsz bytes
          Set blocksize. 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.

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

   --setra sectors
          Set readahead (in 512-byte sectors).

   --setro
          Set read-only.

   --setrw
          Set read-write.

AUTHOR

   blockdev was written by Andries E. Brouwer and rewritten by Karel Zak.

AVAILABILITY

   The blockdev command is part of the util-linux package and is available
   from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

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Free and Open Source Software