Microsoft finally added the ability to compare two workbooks in Excel 2013: https://support.office.com/en-us/article/Basic-tasks-in-Spreadsheet-Compare-f2b20af

Microsoft finally added the ability to compare two workbooks in Excel 2013: https://support.office.com/en-us/article/Basic-tasks-in-Spreadsheet-Compare-f2b20af8-a6d3-4780-8011-f15b3229f5d8 https://support.office.com/en-us/article/Basic-tasks-in-Spre... Not a command line tool, and no API, but they delivered the basic feature. As far as I can tell, it isn't used very much.