Thank you all for the responses. Yep, I had guessed something similar about the placement/order of new entries in the directory file, but still wanted a confirmation. Work-around like close-and-reopen, rewinddir(), etc... work well. And for those of you who wanted to know what the "new" files meant, and what I did with those, here it is: I consolidate the files written to a common network location by multiple processes running on various servers. So in each iteration, I check if any new files (files with different names than the ones I have encountered so far) have been created in the directory. If yes, I open read handlers to those files and push them onto a hash. I then iterate through all the file handlers, read any new lines, and write them all to the output file.