Zenity folder selector for PDFgrep in Ubuntu

#!/usr/bin/python
#/home/clockworkpc/bin/pdfsearch.py

# Released under a GPLv3 Licence by Clockwork PC 2012
# www.clockworkpc.com.au

# You are entitled to the following four freedoms:
# Freedom 0: To run this program for any purpose
# Freedom 1: To study how this program works and change it to make it do what you wish
# Freedom 2: To redistribute copies so you can help your neighbour
# Freedom 3: To distribute copies of your modified version to others

import os
import subprocess

#Get folder using Zenity GUI
proc = subprocess.Popen('zenity --file-selection', shell=True, stdout=subprocess.PIPE, )
output = proc.communicate()[0].strip()
searchFolder = output + "/*.pdf"

#Define the search term  and prepare the Shell command for the commandline application pdfgrep
searchTerm = raw_input("What is the search term? ")
searchPrefix = "pdfgrep -i -H -n "
searchCMD = searchPrefix + '"' + searchTerm + '" ' + searchFolder
print searchCMD

#Execute pdfgrep
os.system(searchCMD)