diff --git a/README.md b/README.md
index 9061bc7..627eea4 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,10 @@
 # postabuse
 
-Check Post's CSV export for abuse of your barcode shipping labels.
\ No newline at end of file
+Check Post's CSV export for abuse of your barcode shipping labels.
+
+Example:
+
+./check_postcsv.py /data/postarchiv/
+
+
+(/data/postarchiv/ being the folder where you store all your csv's from post)
\ No newline at end of file
diff --git a/check_postcsv.py b/check_postcsv.py
new file mode 100755
index 0000000..8561009
--- /dev/null
+++ b/check_postcsv.py
@@ -0,0 +1,46 @@
+#!/usr/bin/python
+
+import csv, sys, os, glob
+
+tr_list = []
+dub_tr = []
+dub_detected = 0
+
+
+dirname = sys.argv[1]
+print "Verwende Verzeichnis", dirname
+
+dirlist = os.listdir(dirname)
+for fname in dirlist:
+  fbase, fext = os.path.splitext(fname)
+  fullfname = os.path.join(dirname, fname)
+  print fname, fbase, fext
+  if fext != ".csv":
+    print "Ueberspringe Datei", fname
+    continue
+
+  print "Verarbeite Datei", fullfname
+  with open (fullfname, 'rb') as fobj:
+    d = csv.reader(fobj, delimiter=';', quoting=csv.QUOTE_ALL)
+    # skip header
+    d.next()
+    for r in d:
+      #print r
+      tr_id = r[8].replace("=", "")
+      if tr_id in tr_list:
+        print "double detected"
+        dub_detected += 1
+        dub_tr.append(r)
+        print r[7], tr_id
+      else:
+        tr_list.append(tr_id)
+
+    
+print "***********************"    
+print "Dubletten erkannt:", dub_detected    
+print "***********************"    
+
+for dub in dub_tr:
+  #print dub
+  print dub[0], dub[4], dub[5], dub[6], dub[7], int(dub[8].replace("=", "").strip('"'))
+