Ender 3 UART gcode drip feed

i was able to get a terminal in linux with dev/ttyS4 communicating in both directions. I can send and recieve codes one at a time. all good. what about sending 1000 lines of gcode. can I send at once or do I drip feed? how do I manage flow control and buffer overrun? Im at 115200 baud and so far no problem. I can get the position with G92 so if there is no easy way I can just check where I am with G92 after each line with a script that decides to wait for advance. any advice? thoughts? should I build this in mach4? or just python under linux?