====== dd ======

Copy a file, converting and formatting according to the operands.

===== Usage =====

Disk speed test:

<code bash>
dd if=/dev/zero of=test.img bs=1M count=5000 conv=fdatasync 	# write 5GiB file
</code>

===== Reference =====

  * [[http://www.zphj1987.com/2015/03/22/%E6%AD%A3%E7%A1%AE%E7%94%A8DD%E6%B5%8B%E8%AF%95%E7%A3%81%E7%9B%98%E8%AF%BB%E5%86%99%E9%80%9F%E5%BA%A6/|正确用DD测试磁盘读写速度]]