Compare two files for differences in Mac OS X

Have you been in a position where you are making changes but would like to confirm only the changes were made? Or maybe you are making switch configuration changes and would like to compare to another similar switch that is working as a sanity check.

I have installed multiple File comparison tools and found the winner that I now use religiously on my mac.

The tools I have tried in 2008 include in Alphabetical order

Araxis Merge

BBEdit

DiffMerge

ECMerge

Check out this great comparison for others on Wikipedia for File Comparisons.

My quick two cents on the differences between these tools.

My least favorite comparison tool was BBEdit. I can see how it is a strong editor but for file comparisons its really not in the running.

DiffMerge is the tool I was hoping I would like the most because its free. It's not horrible and if you are okay with just comparing on screen then its fine but I also need to export the differences and that is where DiffMerge fell behind. It prints each page with a or b (example page 1a and page 1b) and you could put those pages side by side and see the comparisons that DiffMerge highlighted or noted but I don't want to have to print, I like it as an option.

ECMerge has a very nice report layout and I found the export to HTML was the best choice and then I would have to print to PDF to supply to coworkers. The thing I didn't like about ECMerge was the GUI isn't very friendly and when doing a comparison report if the text was the same it would have it only on one side of the page where I would prefer the text to be on both sides to not give anyone the chance to assume its different.

Araxis Merge is my favorite and of course the most expensive. It also supports both Mac and Windows. The report is also in HTML format and I wish it PDF exporting was an option. So far I have no complaints with the program and recommend trying the 30day trial on this tool. You'll get hooked like I am and end up coughing up the money for this tool. I purchased the Standard edition. The biggest difference I see between pro and standard is that pro you can compare three files and three folders instead of just two.