Print stdin, but only scroll the most recent n lines to avoid clutter

scrollback.py

#! /usr/bin/env python3

import sys
import time

n = 5
if len(sys.argv) > 1:
    n = int(sys.argv[1])

# Save the cursor position
print("\033[s", end='')
lines = []
while True:
    try:
        line = input()
    except EOFError:
        break

    # Clear the screen below the cursor
    print("\033[0K", end='')
    # Clear the screen above the cursor until saved position
    print("\033[3J", end='')

    lines.append(line)
    lines = lines[-n:]
    # Restore the cursor position
    print("\033[u", end='')
    for l in lines:
        print(l)