I would like to modify the script shown below, so that if re-run, it does not overwrite pre-existing data, but instead writes the rows under it.
(I use the google spreadsheet)
moveValuesOnly fonction () {
var ss = SpreadsheetApp.getActiveSpreadsheet ();
var source = ss.getRange ("Sheet1 F1: H3 ');
source.copyTo (ss.getRange ("Feuil2 A1! '), {contentsOnly: true});
source.clear ();
}