addremove: print meaningful error message if --similar not numeric
adding helloabort: '\n' and '\r' disallowed in filenamesadding helloabort: '\n' and '\r' disallowed in filenamesadding helloabort: '\n' and '\r' disallowed in filenamesadding helloabort: '\n' and '\r' disallowed in filenamesf hello hellof hello hello