Adding nbconvert subcommand.

IPython/terminal/ipapp.py

@@ -81,6 +81,8 b' ipython help profile # show the help for the profile subcmd'
 
 ipython locate             # print the path to the IPython directory
 ipython locate profile foo # print the path to the directory for profile `foo`
+
+ipython nbconvert           # convert notebooks to/from other formats
 """
 
 #-----------------------------------------------------------------------------
@@ -244,6 +246,9 b' class TerminalIPythonApp(BaseIPythonApplication, InteractiveShellApp):'
         history=('IPython.core.historyapp.HistoryApp',
             "Manage the IPython history database."
         ),
+        nbconvert=('IPython.nbconvert.nbconvertapp.NbConvertApp',
+            "Convert notebooks to/from other formats."
+        ),
     ))
 
     # *do* autocreate requested profile, but don't create the config file.