Update a list/buffer of typed characters on one line. Shift the list to the left one space when list exceeds desired length. Polls keyboard for input then updates display. Useful for CLI or other interfaces.

typed_chars.py

import os
import tty
import sys
import termios

# live typed-character buffer
# https://github.com/av1d

the_list = ["1", "2", "3", "4", "5"]

def printList():
    os.system('clear')        # refresh screen
    print (''.join(the_list)) # place delimiter char between ''

def _getInput():              # get kb input
   fd = sys.stdin.fileno()
   old_settings = termios.tcgetattr(fd)
   try:
      tty.setraw(fd)
      ch = sys.stdin.read(1)
   finally:
      termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
   return ch

printList()                                 # print list for the first time

while True:
    try:
        dialed = _getInput()                # poll for kb input

        if dialed in ("x", "X"):            # if x or X is pressed then exit
            sys.exit()
        else:
            the_list.append(str(dialed))    # add element to list
            printList()                     # clear screen & reprint list

        countList = len(the_list)           # count elements

        if countList >= 21:                 # if we hit 20 chars then shift list left one place
            the_list.pop(0)
            printList()                     # clear & reprint
    except:
        sys.exit(0)                         # exit on any errors