diff --git a/processing/post/addCurl.py b/processing/post/addCurl.py
index f5db77234..e368dc482 100755
--- a/processing/post/addCurl.py
+++ b/processing/post/addCurl.py
@@ -70,7 +70,7 @@ Deals with both vector- and tensor fields.
 
 """, version = scriptID)
 
-parser.add_option('-p','--pos','--periodiccellcenter'
+parser.add_option('-p','--pos','--periodiccellcenter',
                   dest = 'coords',
                   type = 'string', metavar = 'string',
                   help = 'label of coordinates [%default]')
diff --git a/processing/post/addDivergence.py b/processing/post/addDivergence.py
index 52ec2df75..d62c02fda 100755
--- a/processing/post/addDivergence.py
+++ b/processing/post/addDivergence.py
@@ -56,7 +56,7 @@ Deals with both vector- and tensor-valued fields.
 
 """, version = scriptID)
 
-parser.add_option('-p','--pos','--periodiccellcenter'
+parser.add_option('-p','--pos','--periodiccellcenter',
                   dest = 'coords',
                   type = 'string', metavar = 'string',
                   help = 'label of coordinates [%default]')
diff --git a/processing/post/addGradient.py b/processing/post/addGradient.py
index 7ef042044..aaf1750a7 100755
--- a/processing/post/addGradient.py
+++ b/processing/post/addGradient.py
@@ -60,7 +60,7 @@ Deals with both vector- and scalar fields.
 
 """, version = scriptID)
 
-parser.add_option('-p','--pos','--periodiccellcenter'
+parser.add_option('-p','--pos','--periodiccellcenter',
                   dest = 'coords',
                   type = 'string', metavar = 'string',
                   help = 'label of coordinates [%default]')