Let me see that I have this straight.

You want your code to 'look' like:

-varbindlist => [$myvariable]
[download]

Where the input would be:

-varbindlist => [${$some_variable}]
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And the input $some_variable would be derived from a value in %cmd_table.

In that case, I think that the answer is simply:

my @RESULTS = ();
my $test;
foreach $test (@test_array) {
     my $temp = $session->getrequest(
          -varbindlist => [${$cmd_table{$test}}]
     );
     unless (defined $temp) {
          print("Error in session: %s", $cmd_table{$test});
          push @RESULTS, "error";
     } else {
          push @results, $temp;
     }
}
[download]

Reformat for personal style.

Also note that this will probably cause some issues if you use strict since you're interpolating variable names which could result in various security issues.