Start session scripts cannot run interactively. A start session script runs in an environment created by Horizon 7 and must obtain its input data from that environment.
Start session scripts gather input data from environment variables on the client computer. Start session environment variables have the prefix VDM_StartSession_. For example, the start session environment variable that contains the client system’s IP address is VDM_StartSession_IP_Address. You must ensure that a start session script validates the existence of any environment variable that it uses.
For a list of variables similar to start session environment variables, see “Client System Information Sent to Remote Desktops” in the Configuring Remote Desktop Features in Horizon 7 document.