do not show <instance> in help when not needed

base.py

@@ -83,7 +83,7 @@ class ServiceManager:
     pkg = ''
     revcmd = {}
     USAGE = None
-    main_ins = basename(expanduser('~'))
+    main_ins = None
 
     def __init__(self):
         self.env = {}
@@ -137,7 +137,7 @@ class ServiceManager:
         for ins in parser.sections():
             section = dict(parser[ins])
             if ins == 'MAIN':
-                ins = self.main_ins
+                ins = self.main_ins = basename(expanduser('~'))
             command = section.get('%s_command' % self.group)
             self.revcmd[command] = self.group
             nr = section.get(self.group)
@@ -410,5 +410,9 @@ class ServiceManager:
             raise
 
     def usage(self):
-        print(self.USAGE % ', '.join(self.info))
+        if self.main_ins:
+            usage = self.USAGE.replace(' <instance>', '').replace(' [<instance>]', '') % ''
+        else:
+            usage = self.USAGE % ('<instance> is one of %s' %  ', '.join(self.info))
+        print(usage)
 

frappyman.py

@@ -36,7 +36,7 @@ class FrappyManager(ServiceManager):
       frappy stop <instance> [<service>]
 
       <service> is one of main, stick, addons
-      <instance> is one of %s
+      %s
     """
 
     def prepare_start(self, ins, service):

nicosman.py

@@ -65,7 +65,7 @@ class NicosManager(ServiceManager):
       nicos link <instance>              (create links to nicos data and scripts)
 
       <service> is one of main, stick, addons
-      <instance> is one of %s
+      %s
 
     to be done after the experiment:
       nicos copy                         (copy data and scripts from link)

seaman.py

@@ -51,15 +51,15 @@ class SeaManager(ServiceManager):
     Usage:
 
       sea gui <instance>
-      sea <instance>     # the same as sea gui <instance>
-      sea cli <instance>                 (the same as old seacmd)
-      sea start <instance> <service>
+      sea <instance>        # the same as sea gui <instance>
+      sea cli <instance>    # the same as old seacmd
+      sea start <instance> [<service>]
       sea restart <instance> [<service>]
       sea stop <instance> [<service>]
       sea list [<instance>]
 
       <service> is one of sea, graph
-      <instance> is one of %s
+      %s
     """
 
     def do_cli(self, ins):