查看组信息：[root@localhost soft]# cat /etc/group

[root@localhost soft]# cat /etc/group
root:x:0:
bin:x:1:bin,daemon
daemon:x:2:bin,daemon
sys:x:3:bin,adm
adm:x:4:adm,daemon
tty:x:5:
disk:x:6:
lp:x:7:daemon
mem:x:8:
kmem:x:9:
wheel:x:10:
mail:x:12:mail,postfix
uucp:x:14:
man:x:15:
games:x:20:
gopher:x:30:
video:x:39:
dip:x:40:
ftp:x:50:
lock:x:54:
audio:x:63:
nobody:x:99:
users:x:100:
dbus:x:81:
usbmuxd:x:113:
utmp:x:22:
utempter:x:35:
desktop_admin_r:x:499:
desktop_user_r:x:498:
floppy:x:19:
vcsa:x:69:
rpc:x:32:
rtkit:x:497:
avahi-autoipd:x:170:
abrt:x:173:
cdrom:x:11:
tape:x:33:
dialout:x:18:
wbpriv:x:88:
rpcuser:x:29:
nfsnobody:x:65534:
haldaemon:x:68:haldaemon
gdm:x:42:
ntp:x:38:
apache:x:48:
saslauth:x:76:
postdrop:x:90:
postfix:x:89:
pulse:x:496:
pulse-access:x:495:
fuse:x:494:
stapusr:x:156:
stapsys:x:157:
stapdev:x:158:
sshd:x:74:
tcpdump:x:72:
slocate:x:21:
qiang:x:500:
mysql:x:27:


查看当前活跃的用户列表：[root@localhost soft]# w

[root@localhost soft]# w
 16:56:50 up 13 min,  2 users,  load average: 0.00, 0.07, 0.08
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     tty1     :0               16:48   13:18   4.34s  4.34s /usr/bin/Xorg :0 -nr -verb
root     pts/0    192.168.1.101    16:52    0.00s  0.27s  0.11s w


查看用户列表：
[root@localhost soft]# cat /etc/passwd|grep -v nologin|grep -v halt|grep -v shutdown|awk -F":" '{ print $1"|"$3"|"$4 }'|more
[root@localhost soft]# cat /etc/passwd|grep -v nologin|grep -v halt|grep -v shutdown|awk -F":" '{ print $1"|"$3"|"$4 }'|more
root|0|0
sync|5|0
qiang|500|500
mysql|27|27