Add cell data to an existing spreadsheet from the command line?

If I already have a spreadsheet with some rows in it, is there any way I can add a new row to the end of the sheet by executing a program on the command line with the data to add? Ideally I want to be able to run the command while the spreadsheet is open and see the update in real time, but I would also be interested in approaches requiring the file to be closed.

If it’s not going to work, would Base be more appropriate in this case?