this is group file:

root::0:root
bin::1:root,bin,daemon
daemon::2:root,bin,daemon,tux
sys::3:root,bin,adm
adm::4:root,adm,daemon
tty::5:
disk::6:root,adm
lp::7:lp
mem::8:
kmem::9:
wheel::10:root
floppy::11:root
mail::12:mail
news::13:news
uucp::14:uucp
man::15:
audio::17:
video::18:
cdrom::19:
games::20:
slocate::21:
utmp::22:
smmsp::25:smmsp
mysql::27:
rpc::32:
sshd::33:sshd
gdm::42:
shadow::43:
ftp::50:
apache:x:80:
messagebus:x:81:
haldaemon:x:82:
plugdev:x:83:
power:x:84:
pop::90:pop
scanner::93:
nobody::98:nobody
nogroup::99:
users::100:
console::101:




AND this the output of the shell (i opened a new one the typed bash):

bash-3.1$ bash
bash-3.1$ groups
bin disk wheel floppy audio video cdrom plugdev