I'm afraid the command was working as expected. % sudo chmod g+s $(which id) % id -g 0 % sudo chmod g-s $(which id) % id -g 100 Regards, Siva Chidambaram Somu On Tue, Aug 30, 2016 at 9:03 AM, Mihai Moldovan wrote: > On 29.08.2016 11:33 AM, Sivachidambaram Somu wrote: > > My bad. I have given below the output of the mount command on my machine. > > > > %mount > > > > /dev/xvda1 on / type auto (rw,noatime) > > > > proc on /proc type proc (rw) > > > > sysfs on /sys type sysfs (rw) > > > > devpts on /dev/pts type devpts (rw,gid=5,mode=620) > > > > tmpfs on /dev/shm type tmpfs (rw) > > > > /dev/mapper/ephemeralVG-ephemeral on /local type ext4 (rw) > > > > none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) > > > > fusectl on /sys/fs/fuse/connections type fusectl (rw) > > Okay, no "nosuid" option in there, so that's also ruled out. > > > As a test, set the setgid bit on the id binary like this: > > sudo chmod g+s $(which id) > > then, as a non-root user(!) run: > > id -g > > Make sure to disable the setgit bit again with: > > sudo chmod g-s $(which id) > > > If the previous id -g call returned an effective group ID of 0, that means > that > setgid functionality should be working on your system. If it's not 0, the > reason > for your problems are likely that setgid on files is not working correctly > on > your system. > > > > Mihai > >