/etc/group

root::0:root
bin::1:root,bin,daemon
daemon::2:root,bin,daemon
sys::3:root,bin,adm
adm::4:root,adm,daemon
tty::5:
disk::6:root,adm,haldaemon
lp::7:lp,altima
mem::8:
kmem::9:
wheel::10:root,altima
floppy::11:root,haldaemon
mail::12:mail
news::13:news
uucp::14:uucp
man::15:man
console::17:
audio::18:haldaemon,altima
cdrom::19:haldaemon,altima
dialout::20:root
tape::26:root
video::27:root,altima
cdrw::80:haldaemon,altima
usb::85:haldaemon,altima
users::100:games,altima
nofiles:x:200:
smmsp:x:209:smmsp
portage::250:portage
utmp:x:406:
nogroup::65533:
nobody::65534:
sshd:x:22:
games:x:35:altima
plugdev:x:440:usbmux,haldaemon,altima
scanner:x:441:altima
messagebus:x:199:
lpadmin:x:106:altima
polkituser:x:105:
cron:x:16:
ldap:x:439:
ntp:x:123:
openvpn:x:104:
fingerprint:x:103:
rpc:x:111:
ssmtp:x:102:
crontab:x:101:
hsqldb:x:999:
haldaemon:x:998:haldaemon
gdm:x:997:
couchdb:x:996:
netdev:x:995:
avahi:x:994:
vnstat:x:993:
guest:x:1000:
altima:x:1001:
dropbox:x:992:altima