1BLOCKDEV(8)                  System Administration                 BLOCKDEV(8)
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NAME

6       blockdev - call block device ioctls from the command line
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SYNOPSIS

9       blockdev [-q] [-v] command [command...]  device [device...]
10       blockdev --report [device...]
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DESCRIPTION

13       The  utility  blockdev  allows one to call block device ioctls from the
14       command line.
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OPTIONS

17       -V     Print version and exit.
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19       -q     Be quiet.
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21       -v     Be verbose.
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23       --report
24              Print a report for the specified device. It is possible to  give
25              multiple  devices. If none is given, all devices which appear in
26              /proc/partitions are shown. Note that the partition StartSec  is
27              in 512-byte sectors.
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COMMANDS

30       It is possible to give multiple devices and multiple commands.
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32       --flushbufs
33              Flush buffers.
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35       --getalignoff
36              Get alignment offset.
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38       --getbsz
39              Print blocksize in bytes.
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41       --getdiscardzeroes
42              Get discard zeroes support status.
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44       --getfra
45              Get filesystem readahead in 512-byte sectors.
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47       --getiomin
48              Get minimum I/O size.
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50       --getioopt
51              Get optimal I/O size.
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53       --getmaxsect
54              Get max sectors per request
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56       --getpbsz
57              Get physical block (sector) size.
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59       --getra
60              Print readahead (in 512-byte sectors).
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62       --getro
63              Get read-only. Print 1 if the device is read-only, 0 otherwise.
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65       --getsize64
66              Print device size in bytes.
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68       --getsize
69              Print  device  size (32-bit!) in sectors. Deprecated in favor of
70              the --getsz option.
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72       --getss
73              Print sectorsize in bytes - usually 512.
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75       --getsz
76              Get size in 512-byte sectors.
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78       --rereadpt
79              Reread partition table
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81       --setbsz bytes
82              Set blocksize. Note that the block size is specific to the  cur‐
83              rent  file descriptor opening the block device, so the change of
84              block size only persists for as long as blockdev has the  device
85              open, and is lost once blockdev exits.
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87       --setfra sectors
88              Set filesystem readahead (same like --setra on 2.6 kernels).
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90       --setra sectors
91              Set readahead (in 512-byte sectors).
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93       --setro
94              Set read-only.
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96       --setrw
97              Set read-write.
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AUTHOR

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

103       The blockdev command is part of the util-linux package and is available
104       from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
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109util-linux                        August 2010                      BLOCKDEV(8)