diff --git a/lib/cli.py b/lib/cli.py
index 20190cc816e4bb027229479c563a8efd6710b341..b33c98c8028f88d0f688d95ddb2518a5e372b2a3 100644
--- a/lib/cli.py
+++ b/lib/cli.py
@@ -195,6 +195,7 @@ __all__ = [
   "cli_option",
   "SplitNodeOption",
   "CalculateOSNames",
+  "ParseFields",
   ]
 
 NO_PREFIX = "no_"
@@ -1200,6 +1201,24 @@ def CalculateOSNames(os_name, os_variants):
     return [os_name]
 
 
+def ParseFields(selected, default):
+  """Parses the values of "--field"-like options.
+
+  @type selected: string or None
+  @param selected: User-selected options
+  @type default: list
+  @param default: Default fields
+
+  """
+  if selected is None:
+    return default
+
+  if selected.startswith("+"):
+    return default + selected[1:].split(",")
+
+  return selected.split(",")
+
+
 UsesRPC = rpc.RunWithRPC
 
 
diff --git a/scripts/gnt-instance b/scripts/gnt-instance
index e64ef9349f64282e8852e6775ec94b2060c07061..6d9e0f9cb16b3c26e29234d95cea60b3d681bf97 100755
--- a/scripts/gnt-instance
+++ b/scripts/gnt-instance
@@ -244,12 +244,7 @@ def ListInstances(opts, args):
   @return: the desired exit code
 
   """
-  if opts.output is None:
-    selected_fields = _LIST_DEF_FIELDS
-  elif opts.output.startswith("+"):
-    selected_fields = _LIST_DEF_FIELDS + opts.output[1:].split(",")
-  else:
-    selected_fields = opts.output.split(",")
+  selected_fields = ParseFields(opts.output, _LIST_DEF_FIELDS)
 
   output = GetClient().QueryInstances(args, selected_fields, opts.do_locking)
 
diff --git a/scripts/gnt-job b/scripts/gnt-job
index 3088a1427b45d90398071dc4c357e11ce084cef2..df2ced97dbe554698a616e77b1ab723238a36a5d 100755
--- a/scripts/gnt-job
+++ b/scripts/gnt-job
@@ -61,12 +61,7 @@ def ListJobs(opts, args):
   @return: the desired exit code
 
   """
-  if opts.output is None:
-    selected_fields = _LIST_DEF_FIELDS
-  elif opts.output.startswith("+"):
-    selected_fields = _LIST_DEF_FIELDS + opts.output[1:].split(",")
-  else:
-    selected_fields = opts.output.split(",")
+  selected_fields = ParseFields(opts.output, _LIST_DEF_FIELDS)
 
   output = GetClient().QueryJobs(args, selected_fields)
   if not opts.no_headers:
diff --git a/scripts/gnt-node b/scripts/gnt-node
index 1cb7f7d980e454fa3ddede7a390b2f5048458050..c17e2c64cff63bffcd12905e9c30804761d9c41f 100755
--- a/scripts/gnt-node
+++ b/scripts/gnt-node
@@ -46,6 +46,10 @@ _LIST_DEF_FIELDS = [
   ]
 
 
+#: Default field list for L{ListVolumes}
+_LIST_VOL_DEF_FIELDS = ["node", "phys", "vg", "name", "size", "instance"]
+
+
 #: default list of field for L{ListStorage}
 _LIST_STOR_DEF_FIELDS = [
   constants.SF_NODE,
@@ -188,12 +192,7 @@ def ListNodes(opts, args):
   @return: the desired exit code
 
   """
-  if opts.output is None:
-    selected_fields = _LIST_DEF_FIELDS
-  elif opts.output.startswith("+"):
-    selected_fields = _LIST_DEF_FIELDS + opts.output[1:].split(",")
-  else:
-    selected_fields = opts.output.split(",")
+  selected_fields = ParseFields(opts.output, _LIST_DEF_FIELDS)
 
   output = GetClient().QueryNodes(args, selected_fields, opts.do_locking)
 
@@ -466,11 +465,7 @@ def ListVolumes(opts, args):
   @return: the desired exit code
 
   """
-  if opts.output is None:
-    selected_fields = ["node", "phys", "vg",
-                       "name", "size", "instance"]
-  else:
-    selected_fields = opts.output.split(",")
+  selected_fields = ParseFields(opts.output, _LIST_VOL_DEF_FIELDS)
 
   op = opcodes.OpQueryNodeVolumes(nodes=args, output_fields=selected_fields)
   output = SubmitOpCode(op, opts=opts)
@@ -514,12 +509,7 @@ def ListStorage(opts, args):
 
   storage_type = ConvertStorageType(opts.user_storage_type)
 
-  if opts.output is None:
-    selected_fields = _LIST_STOR_DEF_FIELDS
-  elif opts.output.startswith("+"):
-    selected_fields = _LIST_STOR_DEF_FIELDS + opts.output[1:].split(",")
-  else:
-    selected_fields = opts.output.split(",")
+  selected_fields = ParseFields(opts.output, _LIST_STOR_DEF_FIELDS)
 
   op = opcodes.OpQueryNodeStorage(nodes=args,
                                   storage_type=storage_type,
diff --git a/test/ganeti.cli_unittest.py b/test/ganeti.cli_unittest.py
index a1ae1471a69e4f9467894aac60cbae0e433a8547..77ad4c16e5322d03d7f2ee031004d63aaa19b730 100755
--- a/test/ganeti.cli_unittest.py
+++ b/test/ganeti.cli_unittest.py
@@ -429,5 +429,18 @@ class TestFormatLogMessage(unittest.TestCase):
     self.assert_(cli.FormatLogMessage("some other type", (1, 2, 3)))
 
 
+class TestParseFields(unittest.TestCase):
+  def test(self):
+    self.assertEqual(cli.ParseFields(None, []), [])
+    self.assertEqual(cli.ParseFields("name,foo,hello", []),
+                     ["name", "foo", "hello"])
+    self.assertEqual(cli.ParseFields(None, ["def", "ault", "fields", "here"]),
+                     ["def", "ault", "fields", "here"])
+    self.assertEqual(cli.ParseFields("name,foo", ["def", "ault"]),
+                     ["name", "foo"])
+    self.assertEqual(cli.ParseFields("+name,foo", ["def", "ault"]),
+                     ["def", "ault", "name", "foo"])
+
+
 if __name__ == '__main__':
   testutils.GanetiTestProgram()