import sys,time

for i in range(10):

    sys.stdout.write('***")

can output *************** 

standard input:    stdin

standard output:  stdout

test；

import sys,time

for i in range(30):

    sys.stdout.write('99999')

    sys.stdout.flush

      time.sleep(0.02)

or :

import sys,time

for i in range(30)

      print('*',end='',flush=True)

      time.sleep(0.2)

truncate article characters only left 9  characters.from present cursor position.

file=open(' three gun men'),'a',encoding='utf-8')

    file.truncate(9)

    file.close