Read and write txt file

Hi 

I am writing a teststand sequence that can publish a device's serial number into a text file or ini, (or publish it into the environment) and then having another teststand sequence to read that file or grab that environment variable. 

I can't just combine the two teststand sequences because I have to run a program in the middle and I need the console output of that program on cmd (and potentially jenkins).

When I'm publishing it to environment variable using SetEnvironmentVariable(String, String, EnvironmentVariableTarget) function, I get a .net fatal error from teststand. 

I am able to write into a text file from teststand using cmd, but I am not sure how to read from it in the 2nd program.

Please help ~  and thank you in advance