comand for envirnment varibles in dos

what is the comand for envirnment varibles in dos

the syntax is:

set "environment variable"="value"

So for example you would have:

set ComSpec=C:\WINNT\system32\cmd.exe

or
set OS=Windows_NT

or even with multiple values like:
set PATH=%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem
set PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH

if you are just trying to see what variables are already declared and the values just type SET {ENTER} at the prompt for a list.

ok thanks my teacher was looking for it cose someone asked him in class