Maintaining program code is almost like moving pieces on a chessboard: you can observe column and line changes precisely between moves. However, if this analogy is stretched to imagine a board that has far more than the usual 64 squares, extended over several levels, the human eye is hardly sufficient for spotting changes. Diff programs such as Eskil [1] can be used to help analyze lengthy blocks of code.

Eskil's program interface is unremarkable; software functions are nestled behind very simple menus. Eskil works with Tcl/Tk, so install this first. If necessary, download the software from the website. The "Installation" box provides information on how to do this manually.

Startup

If you start Eskil from the terminal, you can directly invoke files (Listing 1, line 1) or directories (Listing 1, line 2) for comparison. There are some interesting options you can use on the command line, many of which you can read about in Table 1. Alternatively, you can open files in the program interface via the menu item File | Open both … – first left, and then the right.

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