import subprocess w = 7 h = 6 column = 3 process = subprocess.Popen( ["./voerbak"], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=None ) process.stdin.write(bytearray(f"{w} {h}\n", "utf-8")) process.stdin.flush() process.stdin.write(bytearray(f"{column}\n", "utf-8")) process.stdin.flush() # process.stdin.write(b"0\n") # process.stdin.flush() # for c in iter(lambda: process.stdout.read(1), b''): # sys.stdout.write(c) print(process.stdout.readlines(5))