reverse copy option

I cannot find the reverse option for ddrescue. it seems that it dows not exsist or?

what differences is there between ddrescue and dd_rescue? all i can find is that dd_rescue has som more features?

Run info ddrescue and you

Run
info ddrescue
and you will find the full documentation.

In a nutshell, if you run ddrescue without any other arguments than the infile, outfile and log, it will automatically go through the steps to recover your data. It will skip errors and continue to the end of the drive, thus recovering as much data as possible outright. Then it will try to break up the bad spots by reading smaller chunks of them. It will then read the remaining bad spots backwards. If you specify a number of retries in the command line, it will start all over again that many times.

You can start the rescue, stop it, tell it to skip to the end and then read backwards if that's all you want it to do.

But there really is no point. Ddrescue does everything it should to recover the data efficiently. There are corner cases where you want it to do something specific, and you can read those details in the info pages.

dd_rescue does not compare to GNU ddrescue. It's unfortunate that both utilities share the same name. They are very very different.

i believe the -R option runs

i believe the -R option runs the entire program in reverse; instead of starting at the first sector, it starts at the last and runs backwards.

It also depend on the dd

It also depend on the dd version.
That option you say, is quite recent