Section: System Administration (8)
Updated: July 2014
By default, blkdiscard will discard all blocks on the device. Options may be used to modify this behavior based on range or size, as explained below.
The device argument is the pathname of the block device.
The offset and length arguments may be followed by the multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
- -o, --offset offset
- Byte offset into the device from which to start discarding. The provided value will be aligned to the device sector size. The default value is zero.:
- -l, --length length
- The number of bytes to discard (counting from the starting point). The provided value will be aligned to the device sector size. If the specified value extends past the end of the device, blkdiscard will stop at the device size boundary. The default value extends to the end of the device.:
- -s, --secure
- Perform a secure discard. A secure discard is the same as a regular discard except that all copies of the discarded blocks that were possibly created by garbage collection must also be erased. This requires support from the device.:
- -v, --verbose
- Display the aligned values of offset and length.:
- -V, --version
- Display version information and exit.:
- -h, --help
- Display help text and exit.:
The blkdiscard command is part of the util-linux package and is available Linux Kernel Archive