WinMerge is a tool for visual difference display and merging, for both files and directories. It is highly useful for determining what has changed between file versions, and then merging those changes. WinMerge has Unicode support, Flexible syntax coloring editor. Regexp filtering for filenames and lines. Side-by-side line difference and highlights differences inside lines. A file map shows the overall file differences in a location pane. The user interface is translated into several languages.
Compare the files visually using WinMerge Open WinMerge, click on the folder Icon to open the 'Files and Folders' interface. Click the top browse button and locate the original file. I make a habit of having it in the left. You can choose where you want it(left or right), but it's good to do it the same each time. Click the second browse button and locate the file you have been editing. When you click 'ok', the two files will load side by side in the WinMerge window.