This method changes the position of the stream relative to its current position by the amount specified in
offset.
A negative number can be used to move backwards from the current position.
var fileStreamObj = shell.serviceManager.basics.fileStream;
var streamReaderObj = shell.serviceManager.basics.rawStreamReader;
fileStreamObj.openForRead("c:\\temp\\test.txt");
streamReaderObj.stream = fileStreamObj;
//skip 4 character
fileStreamObj.seekRelative(4);
//read the rest of the file
var fileInfo = streamReaderObj.readStringTillEndOfStream("");
fileStreamObj.close();