Unix: Switching default group

edit /etc/group

gpasswd: administer the /etc/group file

newgrp group-name: to switch your default used in file creation or directory access. This starts a new shell. Exit to return to the previous group id. Use the ps command to see if more than one shell is active.

Source

Solved c++ compile problem on Ubuntu

if we cannot compile C++, we need to install this package

sudo apt-get install build-essential

source