This is a repo for the pr2-grant utility. It makes it possible to run the ros_ethercat_loop without requiring root privileges.
If you installed this package from apt-get then you're good to go. (This is definitely the recommended way)
If you compiled this package from source, then you'll need to copy the resulting ethercat_grant executable to /usr/local/bin and add the sticky bit to it: sudo chmod +s /usr/local/bin/ethercat_grant.
Using ethercat_grant makes it possible to not use sudo anymore for running the ethercat main loop. Just use launch-prefix="ethercat_grant" in your launch files for the ros_ethercat_loop.
If we change the scripts/postinst post installation script, it has to be manually copied, commited and pushed to the branch with name debian/ROS_DISTRO/ethercat_grant inside the debian directory (where ROS_DISTRO is one of melodic, noetic...)
e.g. https://github.com/shadow-robot/ethercat_grant-release/tree/debian/noetic/ethercat_grant/debian
See http://answers.ros.org/question/191779/add-postinstall-rule-for-deb-package-creation/