Accidental rm -r on Whole Disk, Data Recovery Advice Wanted

[rcxb]

Well then I guess you do need to learn ddrescue after all:

How to back up a failing hard drive?

ddrescue works well. First pass should read the easy parts and skip big sections of unreadable parts. The other passes will try to fill in any readable bits around the bad sections. Command-line assumes the failing drive is the second (sdb) drive in the system and you have enough space for a copy of the full 4TB: ddrescue -nN -a 500KiB -K10MiB…