gddrescue 1.23-2build1 (riscv64 binary) in ubuntu focal

 The gddrescue tool copies data from one file or block device
 (hard disc, cdrom, etc) to another, trying hard to rescue data
 in case of read errors.
 .
 gddrescue does not truncate the output file if not asked to.
 So, every time you run it on the same output file, it tries to
 fill in the gaps.
 .
 The basic operation of gddrescue is fully automatic. That is,
 you don't have to wait for an error, stop the program, read the
 log, run it in reverse mode, etc. If you use the logfile
 feature of gddrescue, the data is rescued very efficiently (only
 the needed blocks are read). Also you can interrupt the rescue
 at any time and resume it later at the same point.
 .
 Automatic merging of backups: If you have two or more damaged
 copies of a file, cdrom, etc, and run gddrescue on all of them,
 one at a time, with the same output file, you will probably
 obtain a complete and error-free file. This is so because the
 probability of having damaged areas at the same places on
 different input files is very low. Using the logfile, only the
 needed blocks are read from the second and successive copies.
 .
 The logfile is periodically saved to disc. So in case of a crash
 you can resume the rescue with little recopying. Also, the same
 logfile can be used for multiple commands that copy different
 areas of the file, and for multiple recovery attempts over
 different subsets.
 .
 gddrescue aligns its I/O buffer to the sector size so that it
 can be used to read from raw devices. For efficiency reasons,
 also aligns it to the memory page size if page size is a
 multiple of sector size.
 .
 Please note that this is the GNU ddrescue version providing the
 ddrescue executable. The package is named gddrescue because the
 ddrescue version of Kurt Garloff used to have the ddrescue
 package name already.