The code you posted will open every file that exists and passes the -f (entry is plain file) file test.

Unfortunately, it will also open the same output file on each pass of the while loop -- with write permission (not append). Ie, every pass through the loop creates a completely new c:/move/output/test/out.txt file. I suspect this is the reason you believe you are only finding a single file.

To append to the file on each pass, change your open command from open OUT,">C:/move/output/test/out.txt"; to open OUT,">>C:/move/output/test/out.txt"; You should also consider checking the return value of open.