How to run a script at start-up

Startup items are directory bundles which contain, at a minimum, an executable file and a property list text file. For a startup item named "Foo", the bundle will be a directory named "Foo" containing (at a minimum) an executable "Foo" and a plist file "StartupParameters.plist".

1. Mkdir a new directory for your script in the startup folder /Library/StartupItems E.g.

   mkdir /Library/StartupItems/Greeting

2. Put your script in the directory you just created, in a file of the same name. e.g.

   #!/bin/sh
   
   ##    
   # Do my Greeting
   ##    
   
   . /etc/rc.common
        
   if [ "${FIREWALL:=-NO-}" = "-YES-" ]; then 
       ConsoleMessage "Adding Firewall Rules"
        
      ipdeny=`cat /Documents/Firewall/Firewall.deny | sort | uniq` 
      ipallow=`cat /Documents/Firewall/Firewall.allow | sort | uniq` 
        
      # allow first
      counter=2000
      for i in ${ipallow}; do
       ipfw add $counter allow all from $i to any
       counter=`expr $counter + 1`
      done    
        
      # deny second
      counter=`expr $counter + 1000` 
      for i in ${ipdeny}; do
       ipfw add $counter deny all from $i to any
       counter=`expr $counter + 1`
      done    
        
   fi
   

   "chmod +x Greeting" the shell script file

3. Also in the dir you just created, add these (or similar) lines to file StartupParameters.plist

   {
     Description     = "HAL9000 greeting";
     Provides        = ("Greeting");
     OrderPreference = "Last";
     Messages =
     {
       start = "speaking greeting";
       stop  = "greeting going away";
     };
   }
   

   The above example is written in the old NeXT-style property list format for compactness. But the new XML property lists are also handled. You may prefer using PropertyListEditor.app to editing the property list files manually.

   The plist file contains parameters which tell SystemStarter some information about the executable, such as what services is provides, which services are prerequisites to its use, and so on. The plist contains the following attributes: Description, Provides, OrderPreference, etc.

4. chmod -R 755 /Library/StartupItems/Greeting
   chown -R root:admin /Library/StartupItems/Greeting
   chgrp -R root:admin /Library/StartupItems/Greeting
   For security reasons (because they are executed by root), these startup bundles don't execute unless root owns them.

5. As root, edit /etc/hostconfig which defines several Yes or No variables. Add the "GREETING=-YES-" line.

Startup items may be placed in the "Library" subdirectory of the primary file domains ("System", "Local", and "Network"). The search order is defined by routines defined in NSSystemDirectories.h: Local, then Network, then System. However, because the Network mounts have not been established at the beginning of system startup, bundles in /Network is currently not searched.