title: Append a directory to Amazon Lambda Environment Variables $NODE_PATH
body: <p>Default Env Variable as per the <a href="https://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html#lambda-environment-variables" rel="noreferrer">docs</a>:</p>
  
  <pre><code>NODE_PATH:/opt/nodejs/node8/node_modules/:/opt/nodejs/node_modules:$LAMBDA_RUNTIME_DIR/node_modules
  </code></pre>
  
  <p>I want to append my custom directory to it (NOT to override all)</p>
  
  <pre><code>NODE_PATH:$NODE_PATH:/opt/nodejs/mycustom-directory
  </code></pre>
  
  <p>I tried the above from lambda console it overrides all. <code>$NODE_PATH</code> is added as a string. It is not parsing <code>$NODE_PATH</code></p>
  
  <p>Output I got when printing env:</p>
  
  <pre><code>NODE_PATH=$NODE_PATH:/opt/nodejs/mycustom-directory
  </code></pre>
  
  <p>Similar Question but no Solution still: <a href="https://stackoverflow.com/questions/47136472/aws-lambda-add-path-variable">AWS lambda add PATH variable?</a></p>