--- a/toolfactory/rgToolFactory2.xml	Sat Dec 05 04:34:19 2020 +0000
+++ b/toolfactory/rgToolFactory2.xml	Sun Dec 06 01:21:06 2020 +0000
@@ -69,7 +69,13 @@
         </repeat>
         <repeat name="history_outputs" title="one or more output file parameters generated by the tool to be added to the user history"
              help="The name will become a history item for users of the new tool you are making containing one of it's outputs">
-            <param name="history_name" type="text" label="Name for this output to appear in new history" optional="false" help="Argparse will also use this name as --[name]"/>
+            <param name="history_name" type="text" label="Name for this output to appear in new history" optional="false"
+              help="No spaces! Argparse will also use this name as --[name]">
+              <sanitizer invalid_char="_">
+                <valid initial="string.letters,string.digits"/>
+                <add value="_" />
+              </sanitizer>
+            </param>
             <param name="history_format" type="select" multiple="false" label="Select the datatype for this output"
               help="If your datatype is not listed here, it has to be added in galaxy's datatypes_conf.xml" value="tabular">
                <options from_parameter="tool.app.datatypes_registry.upload_file_formats">