非交互写入注册表而不会覆盖

Question

I'm trying to use the reg add command (reg.exe) to write to the registry, but if the value already exists I don't want to overwrite it. Without the /f option it asks for confirmation, which I don't want. With /f it overwrites the value, which I also don't want.

Is there an easy way to add a registry value if it doesn't exist but leave it alone if it does, and not prompt the user?

Answer 1

As per my comment…

Because you have reported having to decline the overwrite prompt, I would suggest you pipe the expected N into your REG command:

Echo N|Reg Add "HK…… >Nul

Answer 2

As reg returns errorlevels it can be as simple as
(using conditional execution on && success or || fail )

reg query "hkcu\console" /V ColorTable15 >NUL 2>&1  &&( echo Val exists) ||(echo Val not there)
Val exists

reg query "hkcu\console" /V ColorTable16 >NUL 2>&1  &&( echo Val exists) ||(echo Val not there)
Val not there