awk

AWK
[root@liuzan ~]# awk -F ':''OFS=":" {print $3,$1}' 1.txt awk常用用法
0:root
1:bin
2:daemon
3:adm
4:lp

Awk ‘/user|root/’ 1.txt 匹配user或root行
Awk ‘/r*o/’ 1.txt 匹配0个或多个
Awk ‘/r?o/’ 1.txt 匹配0个或1个
Awk ‘/r+o/’ 1.txt 匹配一个或多个
root@liuzan ~]# awk '/(oo)/' 1.txt 匹配00的行
root:x:0:0:root:/root:/bin/bash
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/syooooooooooooooooonc
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin
operator:x:11:0:operator:/root:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin

awk -F ':' '$1~/r*o/' 1.txt 匹配第一段中符合r*o的行
root:x:0:0:root:/root:/bin/bash
daemon:x:2:2:daemon:/sbin:/sbin/nologin
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
operator:x:11:0:operator:/root:/sbin/nologin
gopher:x:13:30:gopher:/var/gopher:/sbin/nologin
nobody:x:99:99:Nobody:/:/sbin/nologin
postfix:x:89:89::/var/spool/postfix:/sbin/nologin

[root@liuzan ~]# awk -F ':' '$1~/r*o/{print $1,$3}; $1~/user/ {print $1,$3}' 1.txt 匹配第一段中有r*o的行和有user的行，2次过滤
root 0
daemon 2
shutdown 6
operator 11
gopher 13
nobody 99
postfix 89
user3 506

awk -F ":" '$1~/r*o|nobody/{print $1,$3}' 1.txt 匹配r*o或nobody的行一次过滤
root 0
daemon 2
shutdown 6
operator 11
gopher 13
nobody 99
postfix 89