sdds2stream APS.twi -parameters=nux,nuy -delimiter=" "
To output values of columns ElementName and betax for the first data page:
sdds2stream APS.twi -column=ElementName,betax -page=1
sdds2stream {inputFileList | -pipe[=input]} [-page=pageNumber] [-delimiter=delimitingString] { -columns=columnName[,columnName...] | -parameters=parameterName[,parameterName...] | -arrays=arrayName[,arrayName...] } [-filenames] [-rows[=bare]] [-npages[=bare]] [-noquotes] [-ignoreFormats] [-description]