diff --git a/scripts/tgt-concatenate-textgrids.py b/scripts/tgt-concatenate-textgrids.py
index ae8131c..ba25b6c 100644
--- a/scripts/tgt-concatenate-textgrids.py
+++ b/scripts/tgt-concatenate-textgrids.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-# Concatenate Praat TextGrid files.
+# tgt-concatenate-textgrids - Concatenate Praat TextGrid files.
 # Copyright (C) 2011-2016 Marcin Włodarczak, Hendrik Buschmeier
 #
 # This program is free software: you can redistribute it and/or modify
diff --git a/scripts/tgt-extract-part.py b/scripts/tgt-extract-part.py
index 4977b2a..02ecae1 100644
--- a/scripts/tgt-extract-part.py
+++ b/scripts/tgt-extract-part.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-# Extract part of a TextGrid.
+# tgt-extract-part.py - Extract part of a TextGrid.
 # Copyright (C) 2015 Marcin Włodarczak
 # 
 # This program is free software: you can redistribute it and/or modify
diff --git a/scripts/tgt-print-tiernames.py b/scripts/tgt-print-tiernames.py
index 634305c..2fa3dff 100755
--- a/scripts/tgt-print-tiernames.py
+++ b/scripts/tgt-print-tiernames.py
@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 
-# print-tiernames.py - Prints the tier names of a textrid file
+# tgt-print-tiernames.py - Prints the tier names of a TextGrid
 # Copyright (C) 2012 Hendrik Buschmeier
 # 
 # This program is free software: you can redistribute it and/or modify
diff --git a/scripts/tgt-shift-boundaries.py b/scripts/tgt-shift-boundaries.py
index c554bb7..15d5322 100755
--- a/scripts/tgt-shift-boundaries.py
+++ b/scripts/tgt-shift-boundaries.py
@@ -21,9 +21,11 @@
 # If a directory is specified, all tier names of the .TextGrid
 # files contained in this directory are printed.
 
+from __future__ import division, print_function
 
 import argparse
 import os.path
+import sys
 
 import tgt
 
@@ -62,6 +64,7 @@ def main():
 	except IOError:
 		print('An error occurred reading file {file}'.
 				format(file=arguments.file))
+		sys.exit(1)
 	# Create new textgrid
 	if arguments.outfile is None:
 		basename, extension = os.path.splitext(arguments.file)