Learning Perl on Win32 Systems

The Registry

The Windows NT Registry is a database that stores all sorts of information about your system. It includes operating system and hardware information, file extension associations, environment information, application information, and much more. In addition to being used heavily by the operating system, most Win32 applications keep registration and state information in the Registry. If you’ve never taken a look at it before, you really ought to run the regedit.exe (or regedt32.exe) utility included with your system and take a look at what the Registry contains. For a detailed programmer’s reference to the Windows 95 Registry, you might try Ron Petrusha’s Inside the Windows 95 Registry, published by O’Reilly & Associates.

Many operating system and application behaviors are controlled by Registry data; therefore, one of the most valuable tools an administrator can have at his disposal is an efficient way to update Registry data. Enter Perl’s Win32::Registry package, which provides a powerful interface to the Registry. This package lets you retrieve information from the Registry, as well as add new information and modify or delete existing information.

A strong word of caution is in order before we begin. The Registry contains vital system data and you could render your system inoperable by deleting or changing Registry information. Before modifying the Registry, make certain that you have a good backup of your entire Registry. The exercises in this chapter will only read ...