Script to change text file / flat file

We are a not for profit training organisation who need to tidy up a file for reporting prurposes. We require a script to be run on a flat file (txt format). The logic is: Course code - begins in column position 21 Course outcome - in column position 61 to 62 For course code beginning with VBN, change outcome to 81 For course code equal to 21773VIC delete line / record We will provide a sample file for the winning bidder. The file is large for a text file - 1000's of lines and 1.3 mb in size. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). * * *This broadcast message was sent to all bidders on Sunday Jan 6, 2008 11:34:28 PM: I originally forgot to mention in the bid request: The file is large for a text file - 1000's of lines and 1.3 mb in size. Thanks. ## Platform We operate Windows XP and Vista.