The squeezed text is impairing IDLE's usability for teaching purposes. Typing help() on any built-in type such as str immediately results in a squeeze-button rather than displaying help. The same is true for showing lines from a file read or from a URL. I recommend showing the first 50 to 100 lines and then squeezing the remainder. Also, I think this may be the logic that is slowing down successive print calls in a loop. Try running: for i in range(500): print(i, sep=' ') or even: for i in range(500): print(i, i**2) The output has noticeably slow delays between successive print() calls.