698 Get information from text file

Create a script (php or perl) which will: 1) Duplicate a text file on the server, creating it if it is not present and replacing it if it is (that's because the file is constantly being written to and I don't want to take chances on it being disturbed/damaged 2) Using the copy of the file, which is tab-delimited text, find the number - unduplicated, case-insensitive - of _unique_ values in the column labelled "QPIN_1". (e.g. ee42, fg42, and EE42 could yield two unique values). Should ignore blanks. 3) Also, in a section of code that can be easily commented out, parse the values in that column and get the values of the third and/or four numbers, and display those separately as totals (e.g. with a string formatted as EE1234J, find the number of 1s, 2, 3s, etc. in the third column and then in the fourth column.) Reason: we are encoding values into ID numbers (PINs) and want a count of those values. 4) Comment liberally so we can configure the display of the results easily and change minor elements in future projects. 5) We should be able to run several of these simultaneously for different text files without having them collide or otherwise interact badly. Should be easy to change the original filenames, and the duplicate filenames should be similar. Also, all data is outside public web space and should remain there! 6) Incorporate sensible security precautions and require a password to run. This is for a Linux system running Apache 1.3 and PHP 4.4.