windows - Put filenames in directory into text file with specific parameters

I need to put all filenames in directory (ideally excluding suffix) into text file. So far I'm using

dir /b > filex.txt

but I need to have output in one row and I need to have OR after every filename so I can easily copy these filenames and put them into Windows search.

The output in textfile should looks like this:

file OR file1 OR file2