Windows.XP.in.a.Nutshell.1002005.2Ed [Electronic resources] نسخه متنی

8.6. Exporting and Importing Registry Data with Patches

Hives have an arcane format,
making direct editing all but futile. Fortunately, the
Registry Editor conveniently supports the
importing and exporting of any number of keys and values with

Registry patches . Patches
(.reg files) are ordinary ASCII text files that
can contain anything from a single key to a dump of the entire
Registry.

Registry patches can be created with Registry Editor or a standard
text editor, such as Notepad. You can also use Notepad to view and
modify patches, and then use Registry Editor to reimport the patch.

Patches have many practical uses, including creating local backups of
portions of the Registry as a preventative measure before editing
keys (see the previous section). You can create a Registry key on one
computer and apply it on another, useful for migrating a single
setting or a whole group of settings to any number of Windows
systems. Patches can allow easier editing than with Registry Editor,
and certainly afford quicker and more flexible searches.

To create a Registry patch, highlight the key you want to export and
select File Export. Once
you've chosen a filename, the selected key, any
subkeys, and all their values and respective data will be saved in a
single file with the .reg extension. In
most cases, you wouldn't want to select My Computer
to export the entire Registry, since, for no other reason,
HKLM is enormous and you wouldn't
want to reimport it in any case.

Before making any changes to a Registry key, do a quick backup by exporting the key. Depending on what changes you've made, the Registry might not be identical after reimporting the key, but at least you'll have a record of what the key looked like before the changes.

Importing
.reg files isn't quite as
simple as creating them, partly because of the concept of merging,
and partly because of the potential for harm. It's
important to note that the contents of a Registry patch are merged
with existing keys; they don't simply overwrite
them. So, if a given key contains four keys (apple, pear, banana, and
peach), and you apply a Registry patch (pointing to the same key)
that contains four keys (apple, pear, banana, and pomegranate), the
resulting key will have five keys (apple, pear, banana, peach, and
pomegranate). The existing values and keys will indeed be overwritten
with those in the patch, but any additional values and keys in the
Registry will remain intact.

The format of
.reg files is similar to
.ini files, rather than anything resembling the
way data is displayed in Registry Editor. A section begins with the
full path of a key in square brackets, like this: [section
name]. This is followed by any number of values, each of
the format name="data" (the default value appears
as @="value"). Then, the next key (if any) is
listed, followed by all the values

it contains.
The order of the keys, as well as the order of the values in each
key, is irrelevant. However, if you were to move a key from one
section to another, it would, in effect, be moving the value from one
key to another.

The quotes around value data are only
used for string values; binary values and
REG_EXPAND_SZ values are prefixed with the keyword
hex: and appear without quotes. Similarly,
DWORD values are preceeded by
dword: and appear without quotes. Any backslashes
in value data (found most often in folder paths and Registry paths)
are doubled to distinguish them from the backslashes in key names.

Lastly, the first line in every Registry patch created
in Windows XP and Windows 2000 will be Windows
Registry Editor
Version 5.00, followed by a
blank line. Patches created in Windows 95, 98, and Me will instead
begin with Registry Editor4,
also followed by a blank line. There doesn't appear
to be any difference in the treatment of these two types of patches
by Registry Editor.

Here is an excerpted Registry
patch:

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\mozilla.org\Mozilla\0.9.2 (en)\Main]
"Program Folder Path"="C:\\Documents and Settings\\All Users\Start Menu\\Programs\\Mozilla\\"
"Install Directory"="C:\\Program Files\\Mozilla\\"
[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]
"NoUpdateCheck"=dword:00000001
"Show_ChannelBand"="No"
"Display Inline Images"="yes"
"Show_ToolBar"="yes"
"Check_Associations"="no"
"SmoothScroll"=dword:00000001
"Play_Animations"="yes"
"Play_Background_Sounds"="yes"
"Display Inline Videos"="yes"
"Print_Background"="no"

You may notice that these two keys are in different manufacturer
branches, and wouldn't appear next to one another in
the Registry. If you think about the way Registry patches are
created, you'll realize that the one shown above
couldn't have been created in a single step.
Instead, two different Registry Patches were created, and the
contents of one were cut and pasted into the other using a plain text
editor. As long as you remove the redundant header, this is perfectly
acceptable. In fact, it can be a very convenient way to implement
several Registry changes in one step.

Extra credit question: given the structure of file types discussed
earlier in this chapter, how would you create a single Registry patch
that contains all the necessary information to register a new file
association on any computer? Could you use such a patch to restore
your preferred file type settings if another application were to ever
overwrite them?