Chapter 16. Managing System Services and Configuration
IN THIS CHAPTER
Locating the Mac OS X Configuration Files
Managing User Preferences
Managing System Services
Strong-Arming the System Brute Force Behavior Modification
You've already been introduced to configuring and con trolling the system through GUI utilities such as the control panes. When using older versions of Mac OS, the only access you have to the configuration for the system is through the GUI interface. Now, you have the option of using a GUI or modifying things through the command line. Although you might wonder whether you'd ever want to use the command line for configuration when Apple has provided such nice GUI tools for configuration, we think there are a few arguments to be made for the command line.
Generally, we agree that Apple's GUI tools are nice. Still, they're GUI tools, and that means you need access to the GUI to use them. If you're trying to manage your machine from a remote location (more on this in Chapter 21, "Accessing and Controlling Tiger Remotely"), access to the GUI might not be possible.
Even if you're at the console, it generally takes more time for GUI tools to load and display their interface than it takes to tweak configuration files. Sometimes this doesn't make any difference, but sometimes it's simply annoying to wait for a GUI interface to load when only a few keystrokes are necessary to make the same change.
Configuration files don't need you to change them. A piece of software can make changes to configurations for you. More interestingly, software can change your configurations on a schedule or based on changes that it detects in the operation of the system. This can let you automate things such as location or network settings, as well as a range of other possibilities.
Finally, just to be pedantic, we'll point out that the GUI interface is software running on top of a non-GUI interface. It's possible for the software that creates the GUI interface to be damaged, and for the rest of the system still to be intact enough to run. If you're limited to knowledge of the GUI tools only, you're limited in your ability to fix the situation. Generally, when dealing with Unix-based things, it's safest to have a handle on the command-line configuration and administration tools. For a pure Unix book, we'd say that it is imperative that you avoid the GUI tools and learn to do everything with the command line. For this book, we'll say that it's a good idea to know the command-line tools Apple has done a very good job.
This chapter introduces you to the tools that you need to modify your machine's configuration from the command line and gives you a few examples of things that you can do. You learn further specifics about the use of these tools in chapters such as Chapter 20, "Configuring Advanced Multiuser/Multisystem Cooperation Features," where we detail specific system configuration topics. Specifically, this chapter addresses where to find configuration files, interacting with the defaults database to customize some user preferences, how to manage system services, and how to brute-force your system into doing what you want.