• Command line tools allow you to manually change or save Windows Registry items.Ron Levine/Lifesize/Getty Images
  
  The Windows Registry is a database of information like configurations, processes, applications and settings for the Microsoft Windows operating system. The command line interface is a way to interact with your computer by typing code, and you run these commands from the Command Prompt, which is located within your Windows Start menu. You must know how to write code to use these tools, but they are all free.
  
  

Reg.exe

• This tool is a console tool, which means that it has its own user interface (UI), and it also has its own sub-commands. These subcommands generally pertain to adding, deleting or copying registry entries or subkeys, which is a section of a cipher key. With this tool, you can also select certain subkeys or registry entries, and compare them to one another, or save them in binary format. Other features of this utility include that you can load or unload registry entries, and import entries, values and subkeys into the entry. To do this, however, you must save the items in REG or text format, and you can also export items as REG items. If you want to pull up a particular registry item, then you can run a query to find that item.
  
  

Scanreg.exe

• The Windows Registry Checker tool or Scanreg.exe allows you to backup your registry and system files on a daily basis, but you can only do this once a day. You can back up the following files: System.ini, User.dat, Win.ini and System.dat. This tool can also scan for bad or invalid entries and use a previous day's backup to fix those invalid items, and it will try to fix any registry corruption. Other features of this tool include that you can set up how many registry backups that you would like to take place, and you can set it up to add more files to the backup collection.
  
  

Regcomp

• The Component Registration tool or regcomp allows you to register certain components, including shared libraries and Java components. To install a Java component, however, the data must point to a true Java installation like an application, and you must use the <OfficePath>/program as your current working directory. If you are working in Unix, then the LD_LIBRARY_PATH needs to hold the javaldx tool. This tool also features subcommands, which allow you to write registration data and the location where you need information written to, and you can also use this tool to read common files types from your registry.