diff --git a/teng_ml/data_preprocess.py b/teng_ml/data_preprocess.py
index d15f11f..01e24c2 100644
--- a/teng_ml/data_preprocess.py
+++ b/teng_ml/data_preprocess.py
@@ -1,6 +1,8 @@
 import pandas as pd
 import numpy as np
 import scipy.signal as signal
+import matplotlib as mpl
+mpl.use("TkAgg")  # fixes focus issues for me
 import matplotlib.pyplot as plt
 from time import sleep
 from random import choice as r_choice
@@ -26,7 +28,7 @@ file = "/home/matth/Uni/TENG/teng_2/data/2023-06-28_foam_black_1_188mm_06V001.cs
 
 
 class InteractiveDataSelector:
-    re_file = r'\d{4}-\d{2}-\d{2}_([a-zA-Z_]+)_([a-zA-Z0-9]+)_(\d+(?:\.\d+)?mm)_(\d+V)(\d+)\.csv'
+    re_file = r'\d{4}-\d{2}-\d{2}_([a-zA-Z0-9_]+)_([a-zA-Z0-9]+)_(\d+(?:\.\d+)?mm)_(\d+V)(\d+)\.csv'
     re_index_group_nr = 5  # group number of the index part of the filename
     """
     Go through all .csv files in a directory, split the data and exclude sections with the mouse, then write the sections as single files into a new directory
@@ -57,12 +59,16 @@ class InteractiveDataSelector:
         if not self._in_files:
             raise ValueError(f"No matching files in 'in_dir' = '{in_dir}'")
 
+        self._history: list[tuple[str, list]] = []   # (in_file, [out_files...])
+
         self._keep_index = keep_index
         self.split_at_exclude = split_at_exclude
 
         plt.ion()
         self._fig, self._ax = plt.subplots()
 
+        mpl.rcParams['keymap.save'].remove('s')  # s is used for split
+        mpl.rcParams['keymap.quit'].remove('q')
         self._fig.canvas.mpl_connect("button_press_event", lambda ev: self._fig_on_button_press(ev))
         self._fig.canvas.mpl_connect("key_press_event", lambda ev: self._fig_on_key_press(ev))
 
@@ -72,8 +78,20 @@ class InteractiveDataSelector:
             plt.pause(0.01)
 
     def _set_titles(self):
-        help_str = "[(e)xclude, (S)plit, (w)rite]"
-        self._fig.suptitle(f"{help_str}\ncurret mode: {self._mode}")
+        help_str = "[(e)xclude, (s)plit, (w)rite+next, (U)ndo last file, (Q)uit]"
+        self._fig.suptitle(f"{help_str}\nuse left click to select, right click to undo\ncurret mode: {self._mode}")
+
+    def _undo_file(self):
+        if len(self._history) == 0:
+            print("Nothing to undo")
+            return
+        # delete written files
+        for outfile in self._history[-1][1]:
+            print(f"Deleting '{outfile}'")
+            os.remove(outfile)
+        self._in_files.insert(0, self._history[-1][0])
+        self._history.pop()
+        self._next_file()
 
     def _next_file(self):
         # runtime stuff
@@ -82,7 +100,7 @@ class InteractiveDataSelector:
         self._current_file = self._in_files.pop(0)
         self._current_dataframe = pd.read_csv(os.path.join(self._in_dir, self._current_file))
         self._current_array = self._current_dataframe.to_numpy()
-        # self._current_array = np.loadtxt(os.path.join(self._in_dir, self._current_file), skiprows=1, delimiter=",")
+        self._current_array = np.loadtxt(os.path.join(self._in_dir, self._current_file), skiprows=1, delimiter=",")
 
 
         # plot stuff
@@ -99,8 +117,6 @@ class InteractiveDataSelector:
         self._mode = "exclude" # split or exclude
         self._set_titles()
 
-        self._set_titles()
-
     def _fig_on_button_press(self, event):
         """
         left click: set split / exclude section (depends on mode)
@@ -124,18 +140,30 @@ class InteractiveDataSelector:
 
     def _fig_on_key_press(self, event):
         """
-        S: set split mode
+        s: set split mode
         e: set exclude mode
         w: write and got to next file
+        Q: quit all
         """
-        if event.key == 'S':
+        if event.key == 's':
             self._mode = "split"
         elif event.key == 'e':
             self._mode = "exclude"
         elif event.key == 'w':
             self._save_as_new_files()
+            try:
+                self._next_file()
+            except IndexError:
+                print(f"All files processed.")
+                exit(0)
+        elif event.key == 'U':
+            self._undo_file()
+        elif event.key == 'Q':
+            print(f"Quitting before all files have been processed!")
+            exit(1)
         self._set_titles()
 
+
     def _update_lines(self):
         # print(self._splits, self._excludes)
         ymin, ymax = self._ax.get_ylim()
@@ -206,6 +234,7 @@ class InteractiveDataSelector:
             if len(new_frames[i]) == 0:
                 new_frames.pop(i)
 
+        self._history.append((self._current_file, []))
         for frame in new_frames:
             filename = self._get_next_filename()
             pathname = os.path.join(self._out_dir, filename)
@@ -215,6 +244,7 @@ class InteractiveDataSelector:
             t_column_name = frame.columns[0]
             frame[t_column_name] -= frame.iloc[0][t_column_name]
             frame.to_csv(pathname, index=False)
+            self._history[-1][1].append(pathname)
             print(f"Saved range of length {len(frame.index):04} to {pathname}")
 
 
@@ -223,9 +253,11 @@ if __name__ == "__main__":
     parser = argparse.ArgumentParser("data_preprocess")
     parser.add_argument("in_dir")
     parser.add_argument("out_dir")
-    parser.add_argument("--keep_index", action="store_true")
+    parser.add_argument("-i", "--keep_index", action="store_true")
+    parser.add_argument("-e", "--split_at_exclude", action="store_true")
     ns = parser.parse_args()
 
-    selector = InteractiveDataSelector(ns.in_dir, ns.out_dir, ns.keep_index)
+    selector = InteractiveDataSelector(ns.in_dir, ns.out_dir, keep_index=ns.keep_index, split_at_exclude=ns.split_at_exclude)
     selector.run()
+    exit(2)  # selector should exit in _fig_on_key_press