I have files that are sourced when users are working on a project. The files set environment variables and cd to the correct working directory and automate a few other things for the end users.

One thing I have not been able to figure out is how to change the user to a different group. Files created in a project context should have the project GID instead of the users default GID. I tried the newgroup command but it starts a new shell and breaks the other automation.

Any ideas on how this can be setup?

If the user is being sent to a different directory for that specific project you can put SGID on that directory and make the directory group the one you want. Any subsequent file placed in that directory will get the group of the directory itself. You can add the SGID bit with the chmod command (e.g. chmod 2770 <directory> gives owner and group read, write and execute and the 2 at the front sets the SGID).

What we do here instead of that is give all users their own login then make them "sudo su - <admin> to the admin user for the environment they want. From that point on all there work is owned by that admin user so group isn't an issue.

MensaWater, Your suggestion works like a charm. Thanks for the tip.