A great feature of the Registry Editor is it's ability to import and export registry settings to a text file, this text file, identified by the .REG extension, can then be saved or shared with other people to easily modify local registry settings. You can see the layout of these text files by simply exporting a key to a file and opening it in Notepad, to do this using the Registry Editor select a key, then from the "Registry" menu choose "Export Registry File...", choose a filename and save. If you open this file in notepad you will see a file similar to the example below:


REGEDIT4

[HKEY_LOCAL_MACHINE\SYSTEM\Setup]
"SetupType"=dword:00000000
"CmdLine"="setup -newsetup"
"SystemPrefix"=hex:c5,0b,00,00,00,40,36,02

The layout is quite simple, REGEDIT4 indicated the file type and version, [HKEY_LOCAL_MACHINE\SYSTEM\Setup] indicated the key the values are from, "SetupType"=dword:00000000 are the values themselves the portion after the "=" will vary depending on the type of value they are; DWORD, String or Binary.

So by simply editing this file to make the changes you want, it can then be easily distributed and all that need to be done is to double-click, or choose "Import" from the Registry menu, for the settings to be added to the system Registry.

Deleting keys or values using a REG file
It is also possible to delete keys and values using REG files. To delete a key start by using the same format as the the REG file above, but place a "-" symbol in front of the key name you want to delete. For example to delete the [HKEY_LOCAL_MACHINE\SYSTEM\Setup] key the reg file would look like this:

REGEDIT4

[-HKEY_LOCAL_MACHINE\SYSTEM\Setup]

The format used to delete individual values is similar, but instead of a minus sign in front of the whole key, place it after the equal sign of the value. For example, to delete the value "SetupType" the file would look like:

REGEDIT4

[HKEY_LOCAL_MACHINE\SYSTEM\Setup]
"SetupType"=-

Use this feature with care, as deleting the wrong key or value could cause major problems within the registry, so remember to always make a backup first.

Regedit Command Line Options
Regedit has a number of command line options to help automate it's use in either batch files or from the command prompt. Listed below are some of the options, please note the some of the functions are operating system specific.

regedit.exe [options] [filename] [regpath]
[filename]Import .reg file into the registry
/s [filename]Silent import, i.e. hide confirmation box when importing files
/e [filename] [regpath]Export the registry to [filename] starting at [regpath]
e.g. regedit /e file.reg HKEY_USERS\.DEFAULT
/L:systemSpecify the location of the system.dat to use
/R:userSpecify the location of the user.dat to use
/C [filename]Compress (Windows 98)
/D [regpath]Delete the specified key (Windows 98)
Source: pctools.com