| .\" Copyright 1998 Andries E. Brouwer (aeb@cwi.nl) |
| .\" Copyright 2007 Karel Zak <kzak@redhat.com> |
| .\" |
| .\" May be distributed under the GNU General Public License |
| .TH BLOCKDEV 8 "August 2010" "util-linux" "System Administration" |
| .SH NAME |
| blockdev \- call block device ioctls from the command line |
| .SH SYNOPSIS |
| .B blockdev |
| .RB [ \-q ] |
| .RB [ \-v ] |
| .I command |
| .RI [ command \&...\&] |
| .I device |
| .RI [ device \&...\&] |
| .br |
| .B blockdev |
| .B \-\-report |
| .RI [ device \&...\&] |
| .br |
| .B blockdev |
| .BR \-h | \-V |
| .SH DESCRIPTION |
| The utility |
| .B blockdev |
| allows one to call block device ioctls from the command line. |
| .SH OPTIONS |
| .IP "\fB\-q\fP" |
| Be quiet. |
| .IP "\fB\-v\fP" |
| Be verbose. |
| .IP "\fB\-\-report\fP" |
| 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. |
| .IP "\fB\-h\fR, \fB\-\-help\fR" |
| Display help text and exit. |
| .IP "\fB\-V\fR, \fB\-\-version\fR" |
| Print version and exit. |
| .SH COMMANDS |
| It is possible to give multiple devices and multiple commands. |
| .IP "\fB\-\-flushbufs\fP" |
| Flush buffers. |
| .IP "\fB\-\-getalignoff\fP" |
| Get alignment offset. |
| .IP "\fB\-\-getbsz\fP" |
| Print blocksize in bytes. This size does not describe device topology. It's |
| size used internally by kernel and it maybe modified (for example) by |
| filesystem driver on mount. |
| .IP "\fB\-\-getdiscardzeroes\fP" |
| Get discard zeroes support status. |
| .IP "\fB\-\-getfra\fP" |
| Get filesystem readahead in 512-byte sectors. |
| .IP "\fB\-\-getiomin\fP" |
| Get minimum I/O size. |
| .IP "\fB\-\-getioopt\fP" |
| Get optimal I/O size. |
| .IP "\fB\-\-getmaxsect\fP" |
| Get max sectors per request |
| .IP "\fB\-\-getpbsz\fP" |
| Get physical block (sector) size. |
| .IP "\fB\-\-getra\fP" |
| Print readahead (in 512-byte sectors). |
| .IP "\fB\-\-getro\fP" |
| Get read-only. Print 1 if the device is read-only, 0 otherwise. |
| .IP "\fB\-\-getsize64\fP" |
| Print device size in bytes. |
| .IP "\fB\-\-getsize\fP" |
| Print device size (32-bit!) in sectors. Deprecated in favor of the \-\-getsz option. |
| .IP "\fB\-\-getss\fP" |
| Print logical sector size in bytes \(en usually 512. |
| .IP "\fB\-\-getsz\fP" |
| Get size in 512-byte sectors. |
| .IP "\fB\-\-rereadpt\fP" |
| Reread partition table |
| .IP "\fB\-\-setbsz\fP \fIbytes\fP" |
| 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. |
| .IP "\fB\-\-setfra\fP \fIsectors\fP" |
| Set filesystem readahead (same like \-\-setra on 2.6 kernels). |
| .IP "\fB\-\-setra\fP \fIsectors\fP" |
| Set readahead (in 512-byte sectors). |
| .IP "\fB\-\-setro\fP" |
| Set read-only. The currently active access to the device may not be affected by the change. For example |
| filesystem already mounted in read-write mode will not be affected. The change applies after remount. |
| .IP "\fB\-\-setrw\fP" |
| Set read-write. |
| .SH AUTHORS |
| blockdev was written by Andries E.\& Brouwer and rewritten by Karel Zak. |
| .SH AVAILABILITY |
| The blockdev command is part of the util-linux package and is available from |
| https://www.kernel.org/pub/linux/utils/util-linux/. |
