Ohh, so THAT's why I have to log out and back in to have my group changes take effect. That, along with having to start a new shell to pick up new env vars from ~/.profile, are my two biggest annoyances with the Linux process model. Reminds me a bit of the Windows 98 days when you had to restart to change your IP address. I really wish someone would sit down and figure out how to propagate group and environment changes to already running processes and implement them.