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Dd

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Man page:dd

Usage

shell

dd OPTIONS

Option	Description
`if`	Input file.
`of`	Output file.
`bs`	Read and write up to SIZE at a time (default 512 bytes).
`count`	Copy only N input blocks.
`oflag`	Perform the commands in the comma separated list after each block is written.
`conv`	Perform the commands in the comma separated list once after all data has been written.
`status`	Information to print to stderr. `none`: only errors; `noxfer`: no final transfer statistics; `progress`: periodic transfer statistics.

Use conv=fdatasync to be sure all data was written to the device.

Write ISO into a drive (sudo needed):

shell

dd if=linux.iso of=/dev/sda bs=4M conv=fdatasync

Benchmark write speed of a disk by writing a 2GiB file (for read speed use hdparm):

shell

dd if=/dev/zero of=ddfile bs=1M count=2k conv=fdatasync; rm ddfile

Copy a file into a hard link without breaking the hard link:

shell

dd if=somefile of=hardlink bs=4M conv=notrunc