Initial commit v2.2

README

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+
+REGLN - Windows Rregistry Linking Utility, v2.2
+===============================================
+Copyright (c) 1999, Antoni Sawicki
+
+
+License
+-------
+  This program is placed in Public Domain.
+  Absolutely no warranty is given.
+  Misuse of this application may destroy your operating system.
+  Have a backup handy!
+
+
+Usage instructions
+------------------
+
+  Usage: regln [-v] <link_key>  <target_key>
+         regln  -d  <link_key>
+
+  <link_key> is the new registry link key
+  <target_key> is an existing registry key being linked to
+  -v = volatile, exist in memory only
+  -d = delete link
+
+
+  Regln can either create or delete a registry link.
+
+  To create a registry link you need to have an existing registry key to link 
+  to and decide whenever the link has to be volatile or permanent.
+
+  Volatile links will be stored in the RAM memory and will not be saved in any
+  HIVE file. This is usefull for experimenting because a simple reboot will
+  remove the link. If you don't specify "-v" option the link will be created
+  permanently by default. This is potentially dangerous operation.
+
+  The application uses NT Namespace Paths by default, eg:
+
+  \Registry\Machine\Software\Microsoft
+
+  However for compatibility and ease of use, a conversion function to translate
+  to Win32 key names was implemented in the public release. From now on, you can
+  simply use:
+
+  HKEY_LOCAL_MACHINE\Software\Microsoft
+
+  or:
+
+  HKLM\Software\Microsoft
+
+  Unfortunately the "virtual root keys" like HKEY_CURRENT_USER  and others are
+  only Win32 addition and are not visible from the Native API and therefore
+  it's not possible use them in REGLN. The only valid "root keys" are:
+
+  Win32                    Abbr       Namespace
+  -----------------------------------------------------
+  HKEY_LOCAL_MACHINE       HKLM       \Registry\Machine
+  HKEY_USERS               HKUS       \Registry\User
+
+  Note: For compatibility with scripts and other utilities the root key name "HKU"
+  was added as synonym of HKUS or HKEY_USERS.
+
+  The keys: HKEY_CURRENT_USER, HKEY_DYN_DATA, HKEY_CLASSES_ROOT or any other CANNOT
+  be used by REGLN. No, it is not possible at all.
+
+  Also you cannot create links (or any other keys) directly under the "root keys",
+  for example from one user profile (in HKUS) to another. Also you cannot link
+  HKLM\FREEWARE to HKLM\SOFTWARE etc. If you want to do that,  you have to load up
+  the hive file and link it's all top-level entries. Perhaps it would be possible
+  to do that using Namespace Links, however it's out of scope of this utility.
+
+
+  To Delete a registry link you simply have to specify the link-key name with "-d"
+  option. It does not matter if the link is volatile or not.
+
+
+Examples
+--------
+  regln -v HKLM\Software\TestInc  HKLM\Software\Microsoft
+
+  Will create a temporary link TestInc pointing to Microsoft. If you open Regedit
+  or any other registry editor and go to HKLM->Software and then TestInc you will
+  see exacly same content as in Microsoft key. If you add/delete/change something 
+  in the Microsoft tree, it will be obviously instantly "changed" in TestInc as
+  well. (Remember to refresh display by pressing F5 if you're using the system
+  regedit.exe)
+
+  regln -d HKLM\Software\TestInc
+
+  Will remove the link...
+
+  Now a more advanced example:
+
+  You can rename "HKLM\Software\Microsoft\Windows\CurrentVersion"
+  to "HKLM\Software\Microsoft\Windows\Version1"  and create creatie
+  a following link:
+
+  regln \Registry\Machine\Software\Microsoft\Windows\CurrentVersion 
+        \Registry\Machine\Software\Microsoft\Windows\Version1
+
+
+  This will create a permanent link pointing from CurrentVersion to the existing
+  key Version1. Now copy the whole tree recursively from Version1 to Version2 so
+  that you'll have:
+
+  HKLM\Software\Microsoft\Windows:
+
+      - CurrentVersion --LINK-->> Version1
+      - Version1
+      - Version2
+
+  Now, you change some variables in Version2 and try to re-link the key
+  CurrentVersion to Version2 by executing:
+
+  regln -d \Registry\Machine\Software\Microsoft\Windows\CurrentVersion 
+
+  regln \Registry\Machine\Software\Microsoft\Windows\CurrentVersion 
+        \Registry\Machine\Software\Microsoft\Windows\Version2
+
+  As you can see, you can have several "sets of settings" for various purposes,
+  and swap them around easily. It seems clear that the "CurrentVersion" key was
+  really intended just for that, except it was never fully implemented until now.
+
+  Note you have to extend Registry Quota to have enough space to do things like
+  this. Also most applications will have open handles to the registry keys and
+  will write to the old place so you usualy will have to reboot to use this. 
+  However if the application uses registry dynamically (opens and closes keys),
+  it will work just fine.
+
+
+
+Real life use of Registry Links
+-------------------------------
+  Microsoft Windows uses Registry Links internally for the feature better known as
+  "Last Good Known Configuration" to this day.
+
+  Windows used to have concept of Hardware Profiles prior to Windows XP. The feature
+  allowed to have some Windows settings changed at boot time by selecting one of the
+  profiles. The amount of Hardware Profile dependent settings was rather limited.
+  Regln allows to extend the functionality by making any Windows registry key to 
+  be profile dependent.
+
+  Regln has been used to allow to split various system level settings to be made
+  user dependent by linking them from HKLM to HKUS. Similarly settings that are
+  normally user dependent (HKUS) can be made system wide (HKLM) so that every user
+  will have the same centrally managed settings. This has been extensively used
+  in Terminal Server Edition deployments.
+
+  Registry links have been used to link a group of disperse and unrelated settings
+  to be stored in the same hive file.
+
+  The application has been used to make several user profiles to link their settings
+  to a single "master" user.
+
+  More recently it was reported that Regln was used to solve a problem with daylight
+  saving time and TZInfo over reboot of a EWF enabled device on Windows XP Embedded. 
+
+Credits
+-------    
+    Antoni Sawicki <[email protected]>
+    Tomasz Nowak <[email protected]>
+    Mark Russinovitch <[email protected]>
+
+