The GNU diff and patch utilities let you compare files to generate a patch that describes the changes between files. You can then apply the patch file on that machine or another. You might think to use diff and patch on XML files, since they are just text files -- and depending on your application, diff and patch might serve your needs well. However, as things such as the sequence in which attributes are ordered in an element tag are not important in an XML file, using specific tools that are aware of the XML standard can make seeing differences and sending XML-aware "patch" files much more attractive.