windows - How to append to the user %PATH% from command line

I found plenty of questions like this one on StackExchange but no one work in my specific case.

I would like to easily add literally %FOO% to the user environment variable PATH.

I found the solution below. Unfortunately it doesn't work as expected.

for /f "skip=2 tokens=3*" %a in ('reg query HKCU\Environment /v PATH') do @if [%b]==[] ( @setx PATH "%~a;%FOO%" ) else ( @setx PATH "%~a %~b;%FOO%" )

It doesn't work if:

• The user PATH variable doesn't exist


• The user PATH exists and is empty


• The user PATH is almost 255 char long.

Moreover it doesn't add the %FOO% literally but expands it.

Is there any possibility to easily do it?