> cat TEST_PACKAGE.pm 
package TEST_PACKAGE;
use base 'Exporter';
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(%TEST_HASH);

our %TEST_HASH;
$TEST_HASH{'TEST_KEY'} = 'TEST_VALUE';

1;

##</code><code>##

xterm> ./test.pl '/bin/touch $TEST_HASH{'TEST_KEY'}'    # Would create a touchfile called TEST_VALUE
xterm> ./test.pl 'echo Test key contains $TEST_HASH{'TEST_KEY'}'  # Would echo TEST_VALUE

##</code><code>##

> cat test.pl
#!/usr/bin/perl

my @command = @ARGV;

use TEST_PACKAGE qw(%TEST_HASH);

my $command_string;
for (my $i = 0; $i < scalar(@command); $i++ ) {
        # Interpret each word in the command string and substitute known variables
        $command_string = $command_string . " " . ( sprintf "%s", $command[$i] );
}

print "\nExecuting command: $command_string\n";
system "$command_string";

##</code><code>##

xterm> ./test.pl 'echo Test key contains $TEST_HASH{'TEST_KEY'}'   # One of many trials, with varying escape characters tried
Executing command: echo Test key contains $TEST_HASH{TEST_KEY}
Test key contains {TEST_KEY}