diff --git a/allanplot.py b/allanplot.py
index cc524ad..21f2efa 100644
--- a/allanplot.py
+++ b/allanplot.py
@@ -7,7 +7,7 @@ import matplotlib.pyplot as plt
 
 # Default filename
 FILENAME = '*.dat'
-COLUMNS = [2]
+COLUMNS = '2'
 RATE = 1
 
 #==============================================================================
@@ -18,7 +18,7 @@ def parse():
     :returns: populated namespace (parser)
     """
     parser = argparse.ArgumentParser(description = 'Plot Allan Deviation from timeseries file',
-                                     epilog = 'Example: \'./allanplot.py -f toto.dat\' compute and plot Allan Deviation form toto.dat values')
+                                     epilog = 'Example: \'./allanplot.py -f \'toto.dat\' -c 2 3\' compute and plot Allan Deviation form columns 2 and 3 of toto.dat')
 
     parser.add_argument('-f',
                         action='store',