Text file processing Enhancements

I have a program written in C shell already that takes data from one input file and then creates a new file according to certain prescribed format. I have a definition file that describes the format of the output file and how to process the data from the input file. It needs a little bit of understanding the input file format and the output file format needed but once understood it's a very easy project. Both input and output files are csv files. I will be able to explain the detail of the input and output files and have some documents as help for the programmer to use as reference.