Dd rescue
dd_rescue, is an an advanced evolution of dd, a command line program that has been ported only for UNIX/Linux. The program uses a complex series of flags to allow the user to image or write data from and to raw image files. Like dcfldd, the program makes an effort to keep the user apprised of the status of the current operation.
ddrescue and dd_rescue are completely different programs which share no development between them. The two projects are not related in any way except that they both attempt to enhance the standard dd tool and coincidentally chose similar names for their new programs.
A large difference between ddrescue and dd_rescue is that dd_rescue can pipe output to stdout whereas ddrescue can only transfer block/file to block/file.
Use
Creating a disk image from a device.
dd_rescue /dev/hda myfile.img
Transferring a disk image over the network using ssh.
dd_rescue /dev/sda1 - | ssh user@remote.host "cat - > /remote/destination/file.img"
Adding compression to an image file on the fly.
dd_rescue /dev/sda1 - | bzip2 > /dir/file.img.bz2
Caution
Unlike regular dd, dd_rescue does not use the command
line arguments if or of.