Editing documents, program code, or any data always risks introducing errors. Displaying the differences between two or more sets of data, file comparison tools can make computing simpler, and more efficient by focusing on new data and ignoring what did not change. Generically known as a diff[1] after the Unix diff utility, there are a range of ways to compare data sources and display the results.
Some widely used file comparison programs are diff, cmp, FileMerge, WinMerge, Beyond Compare, and File Compare.
Because understanding changes is important to writers of code or documents, many text editors and word processors include the functionality necessary to see the changes between different versions of a file or document.