Update README.md

README.md

@@ -23,7 +23,7 @@ If the repository was cloned in a standard way, it is possible to checkout submo
 To generate the PDF version of manual(s) use the following:
 
 ```
-./manual_build.sh [-p] [-r version ] manual_name
+./manual_build.sh [-c] [-p] [-r version ] manual_name
 ```
 
 `manual_name` : Chose one model manual among `NEMO`, `SI3`, `TOP`, or `all` (if not provided compile `NEMO`)