diff --git a/bgservice/bgservice.py b/bgservice/bgservice.py
index db0f15e..437cdda 100644
--- a/bgservice/bgservice.py
+++ b/bgservice/bgservice.py
@@ -2,6 +2,7 @@ import time
 import sys
 import os
 import pyinotify
+import checker
 
 
 class EventHandler(pyinotify.ProcessEvent):
@@ -77,18 +78,24 @@ class EventHandler(pyinotify.ProcessEvent):
 
 NOTIFIER = None
 STDOUT = sys.stdout
+DIR = None
+START_TIME = None
 
 
 def watch_dir(watched_dir="/tmp", logdir="/tmp/skooloslogs"):
+    global DIR
+    global START_TIME
+    global NOTIFIER
+    DIR = watched_dir
     if not os.path.exists(logdir):
         os.makedirs(logdir)
     logfile = open(
         logdir + "/skoolos_" +
         time.strftime("%m%d%Y-%H%M%S", time.localtime()), 'w')
     sys.stdout = logfile
+    START_TIME = time.time()
     print("Start time: " +
           time.strftime("%A, %B %d, %Y %H:%M:%S", time.localtime()) + "\n\n")
-    global NOTIFIER
     wm = pyinotify.WatchManager()
     mask = pyinotify.IN_CREATE | pyinotify.IN_CLOSE_WRITE | pyinotify.IN_DELETE | \
         pyinotify.IN_MOVED_TO | pyinotify.IN_MOVED_FROM | pyinotify.IN_OPEN
@@ -99,7 +106,17 @@ def watch_dir(watched_dir="/tmp", logdir="/tmp/skooloslogs"):
 
 def stop_watching():
     NOTIFIER.stop()
+    now = time.time()
     print("End time: " +
           time.strftime("%A, %B %d, %Y %H:%M:%S", time.localtime()))
+    print("\nTotal work time: " +
+          time.strftime("%H:%M:%S", time.gmtime(now - START_TIME)))
+    suspicious_files = checker.file_check(DIR)
+    if suspicious_files != []:
+        print(
+            "\n\n--------------------------------------------------\n\n\n" +
+            "WARNING: One or more file did not have file extensions that are acceptable.\n"
+            + "The paths to these files are listed below:\n")
+        print(*suspicious_files, sep='\n')
     sys.stdout = STDOUT
     print("Done watching.\n")
diff --git a/bgservice/checker.py b/bgservice/checker.py
index 35d48fc..78afdae 100644
--- a/bgservice/checker.py
+++ b/bgservice/checker.py
@@ -1,9 +1,80 @@
 import os
+from glob import glob
+
+file_whitelist = [
+    # text and document files
+    ".doc",
+    ".docx",
+    ".odt",
+    ".pdf",
+    ".rtf",
+    ".tex",
+    ".txt",
+    ".wpd",
+    # video files
+    ".3g2",
+    ".3gp",
+    ".avi",
+    ".flv",
+    ".h264",
+    ".m4v",
+    ".mkv",
+    ".mov",
+    ".mp4",
+    ".mpg",
+    ".mpeg",
+    ".rm",
+    ".swf",
+    ".vob",
+    ".wmv",
+    # spreadsheet files
+    ".ods",
+    ".xls",
+    ".xlsm",
+    ".xlsx",
+    ".csv",
+    # programming files
+    ".c",
+    ".class",
+    ".cpp",
+    ".cs",
+    ".go",
+    ".h",
+    ".java",
+    ".pl",
+    ".sh",
+    ".swift",
+    ".vb",
+    # presentation files
+    ".key",
+    ".odp",
+    ".pps",
+    ".ppt",
+    ".pptx",
+    # image files
+    ".ai",
+    ".bmp",
+    ".gif",
+    ".ico",
+    ".jpeg",
+    ".jpg",
+    ".png",
+    ".ps",
+    ".psd",
+    ".svg",
+    ".tif",
+    ".tiff",
+]
 
 
 def shell_check():
-    bash_history = [line.strip() for line in open(os.path.expanduser("~/.bash_history"), 'r')]
-    zsh_history = [line.strip() for line in open(os.path.expanduser("~/.histfile"), 'r')]
+    bash_history = [
+        line.strip()
+        for line in open(os.path.expanduser("~/.bash_history"), 'r')
+    ]
+    zsh_history = [
+        line.strip() for line in open(os.path.expanduser("~/.histfile"), 'r')
+    ]
     report = "Suspicios commands found:\n"
     for i in bash_history + zsh_history:
         if "git" in i:
@@ -13,5 +84,17 @@ def shell_check():
     return "Nothing suspicious found in bash or zsh history."
 
 
-def file_check(dir_):
+def verify_file(file_):
+    for ext in file_whitelist:
+        if file_[len(file_) - len(ext):] == ext:
+            return True
+    return False
 
+
+def file_check(dir_):
+    files = glob(dir_ + "/**/*", recursive=True)
+    suspicious_files = []
+    for file_ in files:
+        if not verify_file(file_):
+            suspicious_files.append(file_)
+    return suspicious_files
diff --git a/requirements.txt b/requirements.txt
index ceb2027..b4e22a6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -23,6 +23,7 @@ lazy-object-proxy==1.4.3
 mccabe==0.6.1
 meson==0.53.2
 msgpack==0.6.2
+numpy==1.18.5
 oauthlib==3.1.0
 ordered-set==3.1.1
 packaging==20.1
@@ -59,3 +60,4 @@ webencodings==0.5.1
 Werkzeug==1.0.1
 wpgtk==6.1.3
 wrapt==1.12.1
+yapf==0.30.0