How do I reset a user-created environment variable to be empty?

[c.taylor]

I have created an environment variable called "SUFFIX", and assigned it the value "PSI", using the following command sequence:

setenv<enter>SUFFIX<enter>PSI<enter>

It works fine for what I'm doing (a toolbar button macro using DIESEL in AutoCAD LT 2011), but now I want to set the variable SUFFIX to be empty: not a space, not anything at all. I can't figure out a keyboard input that will do that.

Perhaps there is an AutoCAD variable that consists of a null string? If so, I could "$M=" to get that null value and place it in SUFFIX.

Any suggestions? Thanks in advance.

[cadtag]

(setenv "SUFFIX" "")
will set it to ni.

checking the value after that give me:
Command: (getenv "SUFFIX")
nil

[c.taylor]

Thanks, it's a good thought. Unfortunately, it works in AutoCAD, but not in LT. The LT command sequence follows:

Command: SETENV
Enter variable name: SUFFIX
Value: PSI


Command: GETENV
Enter variable name: SUFFIX
PSI

Command: SETENV
Enter variable name: SUFFIX
Value <PSI>: ""


Command: GETENV
Enter variable name: SUFFIX
PSI

[cadtag]

LT -- ok, you might get a better response in the LT Forum. Typing either GETENV or SETENV at a command line here, (c3d 2011) just give me unknowncommand.

However, Adesk often uses a . as a null response - no idea if that would work for you or not, since those commands don't exist here, I can't test them. It would probably return a period at the GETENV command, but maybe,,,

[irneb]

If you want to force this, you could always edit it manually in the registry. Sorry, not sure exactly where the LT registry path is kept, but it shouldn't be a whole lot different from the normal ACad one. E.g. after creating a SUFFIX envvar, I find it in:
HKEY_CURRENT_USER\Software\Autodesk\AutoCAD\R18.2\ACAD-A001:409\FixedProfile\General\

[c.taylor]

Thanks for all the responses.