Linux-正则

常规匹配

[server@hadoop102 ~]$ cat /etc/pd |grep server
server:x:1000:1000:server:/home/server:/bin/bash

特殊字符

[server@hadoop102 ~]$ cat /etc/pd |grep ^a
adm:x:3:4:adm:/var/adm:/sbin/nologin
abrt:x:173:173::/etc/abrt:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

[server@hadoop102 ~]$ cat /etc/pd |grep bash$
root:x:0:0:root:/root:/bin/bash
server:x:1000:1000:server:/home/server:/bin/bash

匹配空行

[server@hadoop102 ~]$ cat /etc/pd |grep ^$
[server@hadoop102 ~]$ cat /etc/pd |grep -n ^$

[root@hadoop102 scripts]# cat /etc/pd |grep r..t
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin

[root@hadoop102 scripts]# cat /etc/pd |grep ro*t
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
abrt:x:173:173::/etc/abrt:/sbin/nologin
rtkit:x:172:172:RealtimeKit:/proc:/sbin/nologin

[root@hadoop102 scripts]# cat /etc/pd |grep ^a.*in$  
adm:x:3:4:adm:/var/adm:/sbin/nologin
abrt:x:173:173::/etc/abrt:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

[root@hadoop102 scripts]# cat /etc/pd |grep ^a.*var.*in$
adm:x:3:4:adm:/var/adm:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin

[root@hadoop102 scripts]# cat /etc/pd |grep r[a,b]t
operator:x:11:0:operator:/root:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

[root@hadoop102 scripts]# cat /etc/pd |grep r[ab]t 
operator:x:11:0:operator:/root:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

[root@hadoop102 scripts]# cat /etc/pd |grep r[a-z]*t
root:x:0:0:root:/root:/bin/bash
operator:x:11:0:operator:/root:/sbin/nologin
libstoragemgmt:x:998:995:daemon account for libstoragemgmt:/var/run/lsm:/sbin/nologin
abrt:x:173:173::/etc/abrt:/sbin/nologin
rtkit:x:172:172:RealtimeKit:/proc:/sbin/nologin
setroubleshoot:x:990:984::/var/lib/setroubleshoot:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin

[root@hadoop102 scripts]# cat kong.txt |grep '\$'
$echo JAVA

[root@hadoop102 scripts]# echo "15912345678" |grep ^1[34578][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]$
15912345678
[root@hadoop102 scripts]# echo "15912345678" |grep -E ^1[34578][0-9]{9}$                                  
15912345678