in reply to Re^4: appending to a file
in thread appending to a file

Without a fair bit of rewriting your original code, you can add a last; after the final call to close() -- this will exit the for my $f(@files) loop.

This isn't the way I'd write the script, personally, but I don't know enough about your file structure to revise it accurately. I'd probably use File::Find to make this a bit simpler.