Closed:Delete all files with a pattern.

Question

[Saroha]

I have thousands of txt files in one folder. Many of them are unnecessary for me. I want to delete all unnecessary files at once. If I do this manually (by opening every file, see it's content and delete it) it will require a lot of time and efforts. But I have some patterns (some words) (words are the content of the file, not the name of the file) that unnecessary files have. My required files do not have these patterns. So unnecessary files can be filtered and deleted using these patterns.

I have attached 2 screenshots of unnecessary files for better understanding. Highlighted word can be used as pattern.