easiest way to pause a command-line python program?

Question

Let\'s say I have a python program that is spitting out lines of text, such as:

while 1:
  print \"This is a line\"

What\'s the easiest way

Answer 1

You could try this implementation for Linux / Mac (and possible other Unices) (code attribution: found on ActiveState Code Recipes).

On Windows you should check out msvcrt.

import sys, termios, atexit
from select import select

# save the terminal settings
fd = sys.stdin.fileno()
new_term = termios.tcgetattr(fd)
old_term = termios.tcgetattr(fd)

# new terminal setting unbuffered
new_term[3] = (new_term[3] & ~termios.ICANON & ~termios.ECHO)

# switch to normal terminal
def set_normal_term():
    termios.tcsetattr(fd, termios.TCSAFLUSH, old_term)

# switch to unbuffered terminal
def set_curses_term():
    termios.tcsetattr(fd, termios.TCSAFLUSH, new_term)

def putch(ch):
    sys.stdout.write(ch)

def getch():
    return sys.stdin.read(1)

def getche():
    ch = getch()
    putch(ch)
    return ch

def kbhit():
    dr,dw,de = select([sys.stdin], [], [], 0)
    return dr <> []

Implementing what you're looking for would then become something like this:

atexit.register(set_normal_term)
set_curses_term()

while True:
    print "myline"
    if kbhit():
        print "paused..."
        ch = getch()
        while True
            if kbhit():
                print "unpaused..."
                ch = getch()
                break