Subtract files from a folder

[wasimsono]

Dear All

I got 12,890 text files in one folder named "mrd-012020" from ftp server and after two days I again get backup from ftp server but this time I got 13,656 text files in "mrd-012020f" folder. Now I want to keep one folder only which have all unique files from both folders. Can I subtract files from one folder to another folder?
I used "Diff" command but didn't get result.

[pieh-ejdsch]

What is diff?
Which specific (different) content have these files?
Test this
viewtopic.php?p=60645#p60645
or You can try doublettes finder?