[root@yonglinux ~]# head -n2 passwd |awk -F: '{print $1}'
root
bin
[root@yonglinux ~]# head -n2 passwd |awk -F: '{print $0}'
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
[root@yonglinux ~]# head -n2 passwd |awk -F: '{print $1,$3,$7}'
root 0 /bin/bash
bin 1 /sbin/nologin

[root@localhost ~]# awk -F: '{print $3,$4}' 1.txt |head -5
0 0
1 1
2 2
3 4
4 7
[root@localhost ~]# awk -F: '{print $3":"$4}' 1.txt |head -5
0:0
1:1
2:2
3:4
4:7
[root@localhost ~]# awk -F: 'OFS="#"{print $3,$4}' 1.txt |head -5
0#0
1#1
2#2
3#4
4#7

[root@yonglinux ~]# head -n2 passwd |awk -F: '{print $1"#""@"$3"#"$7}'
root#@0#/bin/bash
bin#@1#/sbin/nologin

[root@yonglinux ~]# awk -F: '$1~/me/' passwd 
games:x:12:100:games:/usr/games:/sbin/nologin
[root@yonglinux ~]# awk -F: '$1~/user/' passwd 
user1:x:600:501::/home/user1:/bin/bash

[root@yonglinux ~]# awk -F: '/root/ {print $1,$3} /user/ {print $1,$3}' passwd 
root 0
operator 11
ftp 14
saslauth 499
user1 600

root@yonglinux ~]# awk -F: '$3=="0"' passwd 
root:x:0:0:root:/root:/bin/bash
[root@yonglinux ~]# awk -F: '$3==10' passwd 
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin

[root@yonglinux ~]# awk -F: '$3==10 {print $7}' passwd 
/sbin/nologin
[root@yonglinux ~]# awk -F: '$3=="600"' passwd 
user1:x:600:501::/home/user1:/bin/bash

[root@yonglinux ~]# awk -F: '$3>"500"' passwd | sort -t: -k 3 -n 
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
sshd:x:74:74:privilege-separated ssh:/var/empty/sshd:/sbin/nologin
dbus:x:81:81:system message bus:/:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin
nobody:x:99:99:nobody:/:/sbin/nologin
user1:x:600:501::/home/user1:/bin/bash

[root@yonglinux ~]# awk -F: '$3>500' passwd | sort -t: -k 3 -n 
user1:x:600:501::/home/user1:/bin/bash
[root@yonglinux ~]# awk -F: '$3>'500'' passwd | sort -t: -k 3 -n 
user1:x:600:501::/home/user1:/bin/bash

[root@yonglinux ~]# awk -F: '$7!="/sbin/nologin"' passwd 
root:x:0:0:root:/root:/bin/bash
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
user1:x:600:501::/home/user1:/bin/bash
mysql:x:27:27:MySQL Server:/var/lib/mysql:/bin/bash

[root@yonglinux ~]# awk -F: '$3>"5" && $3<"7"' passwd 
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin
user1:x:600:501::/home/user1:/bin/bash

[root@yong ~]# awk -F: '$3>'5' && $3<'7' {print }' passwd
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

[root@yonglinux ~]# awk -F: '$3>$4 && $7=="/bin/bash"' passwd 
user1:x:600:501::/home/user1:/bin/bash

[root@yonglinux ~]# awk -F: '$3<$4 || $7=="/bin/bash"' passwd 
root:x:0:0:root:/root:/bin/bash
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
games:x:12:100:games:/usr/games:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
ftp:x:14:50:ftp user:/var/ftp:/sbin/nologin
user1:x:600:501::/home/user1:/bin/bash
mysql:x:27:27:mysql server:/var/lib/mysql:/bin/bash

[root@yonglinux ~]# head -5 passwd |awk -F: '{print NR":"NF}'
1:7
2:7
3:7
4:7
5:7
[root@yonglinux ~]# head -5 passwd |awk -F: '{print NF}'
7
7
7
7
7
[root@yonglinux ~]# head -5 passwd |awk -F: '{print NR}'
1
2
3
4
5
[root@yonglinux ~]# head -5 passwd |awk -F: '{print $NF}'
/bin/bash
/sbin/nologin
/sbin/nologin
/sbin/nologin
/sbin/nologin

[root@yonglinux ~]# awk -F: '{(tot=tot+$3)};END {print tot};' passwd 
1720

[root@yonglinux ~]# awk -F: '{if ($1=="root") print $0}' passwd 
root:x:0:0:root:/root:/bin/bash

[root@yonglinux ~]# sum=0;for i in `awk -F: '{print $3}' passwd`;do sum=$[($sum+$i)];done;echo $sum
1720