Hello, your situation highlights the importance of always being cautious when performing disk-related operations. If you used the "clean all" command, I have some unfortunate news because this command completely overwrites the entire disk with zeros (I hope that where you saw it, it wasn't executed with the "all" parameter). If you only used the "clean" command, it simply removed all partitions from the disk, and you may be able to recover them fully along with your files or recover the files themselves. As far as I understand, your system disk was divided into several partitions (for the system and data storage). Under no circumstances should you install a system on this disk. Instead, connect this disk to another PC and start by attempting to recover the partition using TestDisk, which is completely free. It can recover deleted and lost partitions, which is your situation. If TestDisk cannot identify or restore the partition back to the disk, you can recover the files themselves by scanning the disk with software like Disk Drill or R-Studio. However, keep in mind that the former allows you to recover up to 500MB for free, and the latter allows you to recover files up to 256KB for free, which not be sufficient in real-world scenarios, so you might need to consider purchasing the appropriate software.
I hope you can recover the files and that your father's files remain safe. In the future, please be careful when executing Terminal commands.
