Can't call a variable inside os.system method in Python : <pre><code>ENV=raw_input("Enter Environment (QA/Prod):")
print(ENV) 
os.system('aws ec2 describe-instances --filters "Name=tag:Environment,Values=ENV" "Name=instance-state-code, Values=16" &gt; FilteredOP')
</code></pre>

<p>Hi,
I am quite noob to Python. Here,
I cannot able to call ENV variable in os.system command. Is there anything wrong with the syntax.  </p>
