diff --git a/crawl.conf b/crawl.conf
old mode 100644
new mode 100755
index ba6dcb5..30e36c6
--- a/crawl.conf
+++ b/crawl.conf
@@ -1,9 +1,11 @@
-# Domain                    Ex: benrmorgan.com
-benrmorgan.com
-# Prefix                    Ex: http://www.
-http://www.
-# Target path               Ex /var/www/html/sitemap.xml or ./sitemaps/sitemap.xml
-/var/www/html/sitemap.xml
-# Ignore urls containing    Ex: /files/
-/files/
-/images/
\ No newline at end of file
+[Config]
+; Domain                    Ex: benrmorgan.com
+domain = benrmorgan.com
+; Prefix                    Ex: http://www.
+prefix = http://www.
+; Target path               Ex /var/www/html/sitemap.xml or ./sitemaps/sitemap.xml
+target = /var/www/html/sitemap.xml
+; Checksums path            Ex ./checksums
+checksums = ./checksums
+; Ignore urls containing    Ex: /files/
+ignore = /files/, /images/
\ No newline at end of file
diff --git a/main.py b/main.py
old mode 100644
new mode 100755
index c2f34fa..7524377
--- a/main.py
+++ b/main.py
@@ -1,23 +1,33 @@
+#!/usr/bin/env python3
+from calendar import different_locale
 import datetime
 import os
-
 import bs4
 from urllib.request import Request, urlopen
 from os.path import exists
 from shutil import move
+from hashlib import md5
+import configparser
 
 
+def get_page_hash(text: str):
+    text = text.replace(' ', '').replace('\r', '').replace('\n', '')
+
+    return md5(text.encode('utf-8')).hexdigest()
+
 def spider(prefix, domain, exclude):
-    return spider_rec(dict(), prefix, domain, "/", exclude)
+    return spider_rec(dict(), dict(), prefix, domain, "/", exclude)
 
 
-def spider_rec(links, prefix, domain, postfix, exclude):
-    links[postfix] = 1
-
+def spider_rec(links, checksums, prefix, domain, postfix, exclude):
     req = Request(prefix + domain + postfix)
     html_page = urlopen(req)
 
     soup = bs4.BeautifulSoup(html_page, "lxml")
+
+    checksums[postfix] = get_page_hash(soup.getText())
+    links[postfix] = 1
+
     for link in soup.findAll('a'):
         href = link.get('href')
         if "mailto:" not in href and (domain in href or href[0] == '/'):
@@ -32,13 +42,14 @@ def spider_rec(links, prefix, domain, postfix, exclude):
                     continue
 
                 href = href.replace(" ", "%20")
+
                 if domain in href:
-                    spider_rec(links, "", "", href, exclude)
+                    spider_rec(links, checksums, "", "", href, exclude)
                 else:
-                    spider_rec(links, prefix, domain, href, exclude)
+                    spider_rec(links, checksums, prefix, domain, href, exclude)
             else:
                 links[href] += 1
-    return links
+    return links, checksums
 
 
 def cmp(p1, p2):
@@ -46,8 +57,6 @@ def cmp(p1, p2):
         with open(p2, 'r') as f2:
             l1 = f1.readlines()
             l2 = f2.readlines()
-            not_matched = []
-
             if len(l1) == len(l2):
                 for i in range(len(l1)):
                     if l1[i] != l2[i]:
@@ -62,22 +71,28 @@ def cmp(p1, p2):
 def main():
     print("Reading conf...")
 
-    conf = []
-    with open('crawl.conf', 'r') as file:
-        for line in file.readlines():
-            if line[0] != '#':
-                line = line.replace("\n", "")
-                line = line.replace("\r", "")
-                conf.append(line)
+    config = configparser.ConfigParser()
+    config.read('crawl.conf')
+    config = config['Config']
 
-    domain = conf[0]
-    prefix = conf[1]
-    path = conf[2]
+    domain = config['domain']
+    prefix = config['prefix']
+    path = config['target']
+    checksums_path = config['checksums']
 
-    ignores = conf[3::]
+    ignores = config['ignore'].split(', ')
+
+    checksums = dict()
+    try:
+        with open(checksums_path, 'r') as checksums_file:
+            for line in checksums_file.readlines():
+                thirds = line.split()
+                checksums[thirds[0]] = (thirds[1:])
+    except FileNotFoundError:
+        print("No checksums file found at path, new file will be created.")
 
     print("Crawling site...")
-    links = spider(prefix, domain, ignores)
+    links, new_checksums = spider(prefix, domain, ignores)
     date = datetime.datetime.utcnow()
 
     existed = exists(path)
@@ -104,21 +119,34 @@ def main():
             level += 1
             old_num = sorted_links[l]
 
-        link = l
-        if link[0] == '/':
-            link = prefix + domain + link
-        ordered.append((link, str(float(str(round(pow(0.8, level), 2))))))
+        ordered.append((l, str(float(str(round(pow(0.8, level), 2))))))
 
+    checksums_out = open(checksums_path, 'w')
+
+    different_count = 0
     for l in ordered:
+        lastmod = date.strftime("%Y-%m-%dT%H:%M:%S+00:00")
+        if l in checksums.keys() and checksums[l[0]] == new_checksums[l[0]]:
+            lastmod = checksums[l[0]][1]
+            different_count += 1
+        
+        checksums_out.write(f"{l[0]} {new_checksums[l[0]]} {lastmod}\n")
+        
+        if l[0] == '/':
+            l = prefix + domain + l[0]
+
         out.write("\t<url>\n")
         out.write("\t\t<loc>" + l[0] + "</loc>\n")
-        out.write("\t\t<lastmod>" + date.strftime("%Y-%m-%dT%H:%M:%S+00:00") + "</lastmod>\n")
+
+        out.write("\t\t<lastmod>" + lastmod + "</lastmod>\n")
         out.write("\t\t<priority>" + str(l[1]) + "</priority>\n")
         out.write("\t</url>\n")
 
     out.write("</urlset>\n")
     out.close()
 
+    checksums_out.close()
+
     if existed and not cmp(oldpath, path):
         print("Creating old sitemap backup...")
         move(oldpath, oldpath + "-old")
@@ -129,5 +157,8 @@ def main():
         os.remove(path)
 
     print("Done.")
+    print(f"Crawled {len(links.keys())} pages.")
+    print(f"Found {different_count} modified pages.")
+
 
 main()