title: how to set environment variable for parent process from child process?
body: <p>how to set environment variable for parent process from child process?</p>
  
  <p>For example: 
  I have PARENT and CHILD processes. CHILD process inherited from PARENT process environment variable called TMP_VARIABLE=777. How can I change the value of TMP_VARIABLE in the CHILD process to 999 that it's value becomes visible to PARENT process as TMP_VARIABLE=999?</p>