diff --git a/install.py b/install.py
index 2eb93ae..08e2152 100755
--- a/install.py
+++ b/install.py
@@ -98,30 +98,40 @@ def router(**opts):
 def pip():
     for user, requirements in pip_requirements.items():
         if user == 'root':
-            filename = join('/root', 'pip_requirements.txt')
-            pipcmd = 'pip3 install -r %s' % filename
+            tmpname = join('/root', 'pip_requirements.tmp')
+            pipcmd = 'pip3 install -r %s' % tmpname
         else:
-            filename = join('/home', user, 'pip_requirements.txt')
-            pipcmd = 'sudo --user %s pip3 install --user -r %s' % (user, filename)
+            tmpname = join('/home', user, 'pip_requirements.tmp')
+            pipcmd = 'sudo --user %s pip3 install --user -r %s' % (user, tmpname)
+        filename = tmpname.replace('.tmp', '.txt')
         content = ''.join('# --- for %s ---\n%s\n' % kv for kv in requirements.items())
-        if write_when_new(filename, content):
-            unix_cmd(pipcmd)
+        if write_when_new(filename, content, True):
+            if doit:
+                os.rename(filename, tmpname)
+                if os.system(pipcmd) == 0:
+                    os.rename(tmpname, filename)
+                else:
+                    os.remove(tmpname)
+            else:
+                print(pipcmd)
+            # unix_cmd(pipcmd, stdout=None)
             show.dirty = True
 
 
 SERVICES = dict(router=router, frappy=frappy)
 
 
-def unix_cmd(command, always=False):
+def unix_cmd(command, always=False, stdout=PIPE):
     if doit or always:
         if not always:
             print('$ %s' % command)
-        return Popen(command.split(), stdout=PIPE).communicate()[0].decode()
+        result = Popen(command.split(), stdout=stdout).communicate()[0]
+        return (result or b'').decode()
     else:
         print('> %s' % command)
 
 
-def write_when_new(filename, content):
+def write_when_new(filename, content, ignore_reduction=False):
     if content is None:
         lines = []
     else:
@@ -135,6 +145,14 @@ def write_when_new(filename, content):
         old = None
     if old == content:
         return False
+    if ignore_reduction:
+        content_set = set(v for v in lines if not v.startswith('#'))
+        old_set = set(v for v in (old or '').split('\n') if not v.startswith('#'))
+        content_set -= old_set
+        if content_set:
+            print('missing packages: %s' % (', '.join(content_set - old_set)))
+        else:
+            return False
     if doit:
         if lines:
             with open(filename, 'w') as fil:
@@ -371,7 +389,7 @@ def handle_config():
         raise
         return False
 
-    actions_dict = {}
+    to_start = {}
     reload_systemd = False
     for service, template_func in SERVICES.items():
         section = service.upper()
@@ -387,32 +405,32 @@ def handle_config():
                 enabled = True
             elif line.strip() == 'ActiveState=active':
                 active = True
-        actions = set()
         if template is None:
             if active:
-                actions.add('stop')
-            elif enabled:
-                actions.add('disable')
+                unix_cmd('systemctl stop %s' % service)
+                show.dirty = True
+            if enabled:
+                unix_cmd('systemctl disable %s' % service)
+                show.dirty = True
         else:
-            if not active:
-                actions.add('restart')
             if not enabled:
-                actions.add('enable')
+                to_start[service] = 'enable'
+            elif not active:
+                to_start[service] = 'restart'
         if write_when_new('/etc/systemd/system/%s.service' % service, template):
             show.dirty = True
             reload_systemd = True
-            if 'enable' in actions:
-                actions.add('restart')
-        actions_dict[service] = actions
+            if template and to_start.get('service') is None:
+                to_start[service] = 'restart'
 
     pip()
     if reload_systemd:
         unix_cmd('systemctl daemon-reload')
-    for service in SERVICES:
-        for action in 'stop', 'restart', 'disable', 'enable':
-            if action in actions_dict[service]:
-                show.dirty = True
-                unix_cmd('systemctl %s %s' % (action, service))
+    for service, action in to_start.items():
+        show.dirty = True
+        if action == 'restart':
+            unix_cmd('systemctl restart %s' % service)
+        unix_cmd('systemctl enable %s' % service)
     return True
 
 
diff --git a/servercfg/apumaster_591fac.cfg b/servercfg/apumaster_591fac.cfg
index ab8febd..2f8fb28 100644
--- a/servercfg/apumaster_591fac.cfg
+++ b/servercfg/apumaster_591fac.cfg
@@ -1,10 +1,12 @@
 [NETWORK]
+; please refer to README.md for help
 enp1s0=192.168.127.1/24
 enp2s0=192.168.2.1/24
 enp3s0=192.168.3.1/24
 enp4s0=dhcp
 
 [ROUTER]
+; please refer to README.md for help
 3000=/dev/ttyUSB0
 5900=192.168.2.33
 8080=192.168.127.254:80