How to recover files "emptied" from trash
There is not an official Apple product or command-line tool to undelete / recover in place these files short of Time Machine having made a copy to another volume or to a snapshot.

I have used Data Rescue in the past and would recommend it. There are many questions here covering how that works and their free support is amazing.

The most important thing is to stop using that computer as soon as possible once you verify if Time Machine has you covered, because all disk activity risks over-writing deleted files, reducing your chance to recover intact data from the free space.



This doesn't help your situation now because the data is already lost, but in the future you can use Time Machine.

Time Machine will backup files, even when the drive is not connected, so be sure to check in case you have a local snapshot you can recover.