Associate a bunch of unassociated file extensions with Notepad++ at once via batch

Question

I've got thousands of files with extensions ".0", ".1", ".2", etc. that I want to associate with Notepad++ (v7.5.8). They currently don't have any file association in Windows (Windows 10). Since they don't have any existing association, the solutions shown here aren't working for me.

Also, I'm looking to associate them in Windows, not in the N++ settings, since I access these files from Windows Explorer.

Answer 1

Much easier than manually associating all the .# files, IMO, would be to set up a catch-all edit mode, using regedit:

• HKEY_CLASSES_ROOT\*\shell: Add Key = Notepad++, set (Default) = Edit with &Notepad++
• HKEY_CLASSES_ROOT\*\shell\Notepad++: Add Key = command, set (Default) to "c:\program files (x86)\notepad++\notepad++.exe" "%1" -- use the correct path to notepad++.exe for your system, and make sure to have the double-quotes around both the path and the %1, to make sure spaces are handled correctly.

Log off and back on, or reboot. Now, on any file in explorer, you should be able to right-click, select Edit with Notepad++, and voila!

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Per-Extension Association (All Users)

Alternately, open up a cmd.exe window (run-as-admin if necessary), and run

assoc .1=DotNumber
ftype DotNumber="c:\program files (x86)\notepad++\notepad++.exe" "%1"
for %n in (0 1 2 3 4 5 6 7 8 9) DO assoc .%n=DotNumber 

If you want more .# extensions, add them to the for loop. If you want to set them from a batch file (setdotn-assoc.bat or setdotn-assoc.cmd) rather than at the cmd.exe prompt, need two % rather than just one, everything else is the same:

assoc .1=DotNumber
ftype DotNumber="c:\program files (x86)\notepad++\notepad++.exe" "%1"
for %%n in (0 1 2 3 4 5 6 7 8 9) DO assoc .%%n=DotNumber

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Per-Extension Association (Just for Current User)

If you're having problems with permissions on All Users, you can try this to do the per-extension association, but just for the current user.

In case you were able to create DotNumber type, ftype DotNumber= to remove the existing definition.

Run the following from the command line (shouldn't even need an Administrator command line this time)

REG ADD     HKCU\Software\Classes\DotNumber                      /ve /d "DotNumber File" /f
REG ADD     HKCU\Software\Classes\DotNumber\Shell                /ve /d "open" /f
REG ADD     HKCU\Software\Classes\DotNumber\Shell\open           /ve /d "open DotNumber file" /f
REG ADD     HKCU\Software\Classes\DotNumber\Shell\open\command   /ve /d "\"c:\program files (x86)\notepad++\notepad++.exe\" \"^%1\"" /f
FOR %n in (0 1 2 3 4 5 6 7 8 9) DO REG ADD HKCU\Software\Classes\.%n /ve /d "DotNumber" /f

And if you want to check if it was written

REG QUERY   HKCU\Software\Classes\DotNumber /S
FOR %n in (0 1 2 3 4 5 6 7 8 9) DO REG QUERY HKCU\Software\Classes\.%n /S