sg 1 User Commands sg execute command as different group ID sg - group -c command The sg command works similar to newgrp but accepts a command. The command will be executed with the /bin/sh shell. With most shells you may run sg from, you need to enclose multi-word commands in quotes. Another difference between newgrp and sg is that some shells treat newgrp specially, replacing themselves with a new instance of a shell that newgrp creates. This doesn't happen with sg, so upon exit from a sg command you are returned to your previous group ID. /etc/passwd User account information. /etc/shadow Secure user account information. /etc/group Group account information. /etc/gshadow Secure group account information. id1 , login1 , newgrp1 , su1 , gpasswd1 , group5 , gshadow5