execute command as different group ID
' sg 'u 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 (Aqt happen with sg ,so upon exit from a sg command you are returned to your previous group ID .
The following configuration variables in /etc/login .defs change the behavior of this tool:
SYSLOG_SG_ENAB (boolean) Enable "syslog" logging of sg activity .
/etc/passwd User account information .
/etc/shadow Secure user account information .
/etc/group Group account information .
/etc/gshadow Secure group account information .