diff --git a/install.py b/install.py
index bf8abbd..beb3af1 100755
--- a/install.py
+++ b/install.py
@@ -173,7 +173,8 @@ def frappy(cfg=None, port=None, requirements='', **kwds):
     if not cfg:
         return None
     req = pip_requirements['l_samenv']
-    req[cfg] = '\n'.join(requirements.split(','))
+    if requirements:
+        req[cfg] = '\n'.join(requirements.split(','))
     if port:
         cfg = '-p %s %s' % (port, cfg)
     with open('/home/l_samenv/frappy/requirements.txt') as f:
@@ -229,6 +230,8 @@ def display(**opts):
 
 def pip():
     for user, requirements in pip_requirements.items():
+        if not requirements:
+            continue
         if user == 'root':
             tmpname = '/root/pip_requirements.tmp'
             pipcmd = ['sudo pip3 install -r', tmpname]
@@ -238,15 +241,14 @@ def pip():
         filename = tmpname.replace('.tmp', '.txt')
         content = ''.join('# --- for %s ---\n%s\n' % kv for kv in requirements.items())
         if content:
-            if write_when_new(filename, content, True):
+            if write_when_new(filename, content, user=='root'):
                 if doit:
                     os.rename(filename, tmpname)
                     if os.system(' '.join(pipcmd)) == 0:
                         os.rename(tmpname, filename)
                     else:
                         os.remove(tmpname)
-            # unix_cmd(pipcmd, doit, stdout=None)
-            show.dirty = True
+                show.dirty = True
 
 
 SERVICES = dict(router=router, frappy=frappy, display=display)