[Tkinter] output "os" in frame

[m_clayton]

Hello to all.
I created a frame and two buttons, I assigned two functions to the buttons, one closes the window, the other displays the / etc / fstab file in the shell.
I would like to be able to view the output of the second function within the frame.

from tkinter import *
import os

#window
mywin=Tk()

#function about to close window
def close_window (root): 
    root.destroy()

#function about to read fstab
def fstab():
    os.system("cat /etc/fstab")

#size window
mywin.geometry("600x400+600+100")
mywin.title('WINDOW')

#text in window
mytext=Label(text='View', fg='white', bg='black', font=('Helvetica',30)).pack()

#button GO!
gobutton=Button(text='GO!', command = fstab).pack()

#frame for my output
myframe=Frame(width=300, height=300).pack()

#button Exit
exitbutton=Button (mywin, text="Exit", command = lambda: close_window(mywin)).pack()

#go mainloop
mywin.mainloop()