Directory Compare is a utility to help you keeping copies of your important directories (documents, programs under development and so on) in a backup hard disk or any other storage system (like 100Mb diskettes). The copy may be opionally saved in a zip file and can be made (semi)automatically or in an interactive way.
I always have two or more copies of my important documents and I refresh them very often. I prefer to save exact copies of my working directories (rather than using some backup program), because it is faster and makes easier to open the old copy to recover some element or part that was better in the previous version.
To make this process easier I wrote, many years ago, the first version of the program, cpy, which is included with my Console Utilities. cpy is a command line program, which makes it very convenient to use from a desktop shortcut that after a single click copies to my backup hard disk all modified elements in my working directories. Users who do not want to remember command lines options may use Cmd Line Shell to have a more user-friendly interface.
Directory Compare is a kind or GUI version of cpy: it has far less options but its visual interface makes it easier to do selective copies. For instance, modern compilers generate an incredible amount of auxiliary data, which speeds up compilation, but takes a lot of storage space. (For instance, the source files of Directory Compare are less than 100 Kb, but the auxiliary files generated by the compiler occupy 7,500 Kb!) Usually you do not want such files in your backup disk: they are very large and can be easily recreated by running the compiler.
cpy may be instructed to ask you for confirmation before copying each file, but this is a boring and error prone process. My strategy is to use cpy to copy everything during program development and then, when I release the software, I delete auxiliary files from my main and backup disks. To improve this approach I wrote Directory Compare: it shows you, side by side, the source and backup directories so that you can easily select the files to be copied (from the source to the target or in both directions) and even delete from both directories auxiliary files.