>perl -e "print $ENV{OS}
Windows_NT

>perl -e "print $ENV{os}
Windows_NT

##</code><code>##

>perl -e "use Win32; print Win32::ExpandEnvironmentStrings('OS')
OS

>perl -e "use Win32; print Win32::ExpandEnvironmentStrings('%OS%')
Windows_NT

>perl -e "use Win32; print Win32::ExpandEnvironmentStrings('OS=%OS%')
OS=Windows_NT

##</code><code>##

>echo %VAR%
%OS%

>perl -e "print $ENV{var}
%OS%

>perl -e "use Win32; print Win32::ExpandEnvironmentStrings('%VAR%')
Windows_NT