title: Can a child process pass the environment variable back to parent process
body: <p>Consider the following:</p>
  
  <pre><code>$ cat t.sh
  echo "This is from t.sh"
  eval "t2.sh"
  echo "\$FROM_t2=$FROM_t2"
  
  $ cat t2.sh
  echo "This is from t2.sh"
  export FROM_t2="env_var_from_t2"
  </code></pre>
  
  <p>I want to read the value of "FROM_t2" created by t2.sh into t.sh. Is this possible?</p>