Dd

dd is used to copy raw data from source to sink, where source and sink can be a block device, file or piped input/output.

Installation
As part of the GNU, it should be already installed with any Gentoo GNU/Linux system.

Usage
The program takes input from, optional manipulates the data and writes to per default.

Examples
Some common tasks where dd is used

Boot-Stick
This should work with any live media as long as the memory stick is large enough.


 * if - defines the source
 * of - defines the sink
 * bs - block size - defines the amount of data read/written at a time, default is 512byte but most modern devices can read/write much faster. It is possible to define different sizes for souce and sink using -ibs and -obs.

Backup MBR
To backup the MBR partition table, dd can be told to only copy the first 512byte:


 * count - is the number of blocks to copy

Manipulate input
As an example we convert any upper case character in a file to lowercase and reverse the input per line, then pipe the default stdout to to display the file:


 * conv=swab - this will revert the input per line by swapping any input byte (writing backwards)
 * conv=lcase - convert any upper case letter to lower case, the opposite is ucase
 * conv=noerror - continue if a read error occurs

External resources

 * man pages for dd