Of course it is.
The following script replaces CRLF in the data by <br> character.
var reader = openTextReader(data.filename,"UTF-8");
var tmpFile = createTmpFile();
var writer = openTextWriter(tmpFile.getPath(),"UTF-8");
var line = null;
while((line = reader.readLine()) != null){
line = line.replace(/(?:\\r\\n)/g, "<br>");
line = line.replace(/(?:\\n)/g, "<br>");
writer.write(line);
}
writer.close();
reader.close();
deleteFile(data.filename);
tmpFile.move(data.filename);
You can adapt it to remove your undesired lines like so:
var reader = openTextReader(data.filename,"UTF-8");
var tmpFile = createTmpFile();
var writer = openTextWriter(tmpFile.getPath(),"UTF-8");
var line = null;
while((line = reader.readLine()) != null){
if(!(line === ':O:0' || line === ':S:0')) writer.write(line);
}
writer.close();
reader.close();
deleteFile(data.filename);
tmpFile.move(data.filename);