How to resolve SAS macro variable in shell script

I am running a shell script via X command within a SAS macro. I want to use a macro variable defined in SAS macro, in my shell script. I know if I pass that macro variable as parameter to shell script, I can resolve that within X command. For example, the following will work fine, I know:

%macro a;

%let var1=test;

X "abc.sh &var1";

%mend;
%a;

with this shell script:

echo "value is $1" >  myfile.txt

--- ## What I want:

%macro a;

%let var1=test;

X "abc.sh";

%mend;

%a;

with this shell script:

echo "value is &val1" >  myfile.txt

--- Is there any way to resolve macro variable in shell script? I did my research but couldn't find anything.