grp(3) - phpMan

chgrp (1)            - change group ownership
chgrp (1p)           - change the file group ownership
getpgrp (2)          - set/get process group
getpgrp (3p)         - get the process group ID of the calling process
grp.h (0p)           - group structure
grpck (8)            - verify integrity of group files
grpconv (8)          - convert to and from shadow passwords and groups
grpunconv (8)        - convert to and from shadow passwords and groups
newgrp (1)           - log in to a new group
newgrp (1p)          - change to a new group
setpgrp (2)          - set/get process group
setpgrp (3p)         - set the process group ID
tcgetpgrp (3)        - get and set terminal foreground process group
tcgetpgrp (3p)       - get the foreground process group ID
tcsetpgrp (3)        - get and set terminal foreground process group
tcsetpgrp (3p)       - set the foreground process group ID