Tkinter Text widget

from tkinter import *

root = Tk(  )

# at top of root, left to right, put a Label, an Entry, and a Button
fram = Frame(root)
Label(fram,text='Text to find:').pack(side=LEFT)
edit = Entry(fram)
edit.pack(side=LEFT, fill=BOTH, expand=1)
edit.focus_set(  )
butt = Button(fram, text='Find')
butt.pack(side=RIGHT)
fram.pack(side=TOP)

# fill rest of root with a Text and put some text there
text = Text(root)
text.insert('1.0',
'''Text widgets are a much more generalized method
for handling multiple lines of text than the Label widget.
Text widgets are pretty much a complete text editor in a window:
''')
text.pack(side=BOTTOM)

# action-function for the Button: highlight all occurrences of string
def find(  ):
    # remove previous uses of tag `found', if any
    text.tag_remove('found', '1.0', END)
    # get string to look for (if empty, no searching)
    s = edit.get(  )
    if s:
        # start from the beginning (and when we come to the end, stop)
        idx = '1.0'
        while 1:
            # find next occurrence, exit loop if no more
            idx = text.search(s, idx, nocase=1, stopindex=END)
            if not idx: break
            # index right after the end of the occurrence
            lastidx = '%s+%dc' % (idx, len(s))
            # tag the whole occurrence (start included, stop excluded)
            text.tag_add('found', idx, lastidx)
            # prepare to search for next occurrence
            idx = lastidx
        # use a red foreground for all the tagged occurrences
        text.tag_config('found', foreground='red')
    # give focus back to the Entry field
    edit.focus_set(  )

# install action-function to execute when user clicks Button
butt.config(command=find)

# start the whole show (go event-driven)
root.mainloop(  )