Brief: This article shows you how to recover deleted files in Linux using command line tool Test Disk. It’s an easy to use tool that almost anyone can use to recover lost files in Ubuntu or other Linux distributions.
Have you ever gotten that horrible feeling? The one you get when you realize that you accidentally deleted files and it’s not even in the trash? Often it is immediately preceded by denial: I know I have another copy of it somewhere.
But rather than going through all the stages of grief, don’t worry. And remember you’re not alone; sooner or later everyone does this.
“Don’t worry?” you counter, “I just erased the only copy of my resume!”
No really, don’t worry. All that’s happened is that it’s been bumped off a list. So long as you don’t write onto the drive, it absolutely still exists. In fact, depending on the size of the file and the free space on your drive deleted files can persist indefinitely—even if you do write on the drive.
“Yes, fine” you say, “I’ll rest easy knowing my resume ‘exists’ in some abstract sense. But so far as I’m concerned if I can’t open, edit or print from it, it doesn’t exist in any practical sense. What would really help would be a way to ‘un-delete’ files. And one that doesn’t require an IT forensics lab.”
Really, don’t worry—you don’t need a lab to recover the deleted files. Furthermore, if you can get past using a primitive GUI, it’s actually easy to do! I’ll show you how to use TestDisk to recover deleted files.
How to recover deleted files in Linux using TestDisk

Let me present a simplified example: I took a clean thumb drive added some files, then deleted one. Now, my system has a feature which will directly delete files from removable media, by-passing the “trash” altogether; that is if I choose to “right” click on a file and then choose “delete”. It still presents a warning, but one click on the “yes” button and the file is gone forever. Or appears to be.
But this time I didn’t get that horrible feeling. And no, not because this is a cooked up scenario. I knew that all I had to do was open the terminal type “testdisk” and hit “enter”. When I did this for the first time I had one of my “Linux moments”. Because if you don’t have it—and I didn’t—it tells you how to get it! Just type “sudo apt install testdisk” and enter and you’ll have it in about 10 seconds.
source : FOSS