在标准输出中从底部打印第三行

Question

Currently i am running this

while p.poll() is None:
    output = p.stdout.readline()
    print output,

What is happening is all the lines are being printed. What i am looking for is to print, usually the 3rd line from the bottom, which contains data on whether the command has executed properly or not.

Additionally is there a way to have like a status bar at the bottom that updates real time using Tkinter Label

Answer 1

Solution, thanks to @TadhgMcDonald-Jensen tip

To print only the third last line (indice -3) in terminal shell window

import Tkinter as *
import subprocess

out = []  # Create empty list
for line in iter(p.stdout.readline, ''):
    out.append(line.rstrip('\n')) # append list
print out[-3] # print item in the list, in this case -3

Or to display in tkinter label

import Tkinter as *
import subprocess

out = []  # Create empty list
for line in iter(p.stdout.readline, ''):
    out.append(line.rstrip('\n')) # append list
window = Tk()
Label(window, text=out[-3]).grid(sticky=W)