外壳程序从文件中读取 IP 地址

Question

我有很长的文件

Feb  2 18:43:05 os sshd[14786]: [ID 800047 auth.info] Connection closed by 2001:778:200:4280::37
Feb  2 18:46:08 os sshd[14788]: [ID 800047 auth.info] Connection closed by 158.129.0.37
Feb  2 18:48:05 os sshd[14790]: [ID 800047 auth.info] Connection closed by 2001:778:200:4280::37
Feb  2 18:48:29 os sshd[14791]: [ID 800047 auth.info] Did not receive identification string from 61.240.144.64
Feb  2 19:46:08 os sshd[14853]: [ID 800047 auth.info] Connection closed by 158.129.0.37
Feb  2 19:48:05 os sshd[14855]: [ID 800047 auth.info] Connection closed by 2001:778:200:4280::37
Feb  2 20:21:42 os sshd[14892]: [ID 800047 auth.info] Accepted keyboard-interactive for evakaz from 2001:778:200:4001:e076:812f:23e7:7e62 port 47889 ssh2
Feb  2 21:20:19 os sshd[14960]: [ID 800047 auth.info] Received disconnect from 2001:778:200:4280::38: 11: disconnected by user
Feb  2 21:21:08 os sshd[14963]: [ID 800047 auth.info] Connection closed by 158.129.0.37
Feb  2 22:31:01 os sshd[15100]: [ID 800047 auth.info] Received disconnect 
from 222.161.4.149: 11:
...
...

在每一行中都有IP地址。是否可以在外壳中只读IP地址（而不是整个文件）？

Answer 1

对于 IPv4：

$ grep -woE '([[:digit:]]+.){3}[[:digit:]]+' file
158.129.0.37
61.240.144.64
158.129.0.37
158.129.0.37
222.161.4.149

对于 IPv6：

$ grep -oE '([[:xdigit:]]+:){7}[[:xdigit:]]+' file
2001:778:200:4001:e076:812f:23e7:7e62

对于两者：

$ grep -oE '([[:xdigit:]]+:){7}[[:xdigit:]]+|([[:digit:]]+.){3}[[:digit:]]+' file
158.129.0.37
61.240.144.64
158.129.0.37
2001:778:200:4001:e076:812f:23e7:7e62
158.129.0.37
222.161.4.149

Answer 2

我建议你不要重新发明与IP地址匹配的轮子：

perl -MRegexp::Common=net -nE '
    say $1 if /$RE{net}{IPv4}{-keep}/; 
    say $1 if /$RE{net}{IPv6}{-keep}/
' file

这确实需要您从CPAN安装Regexp：：Common。

从您的输入中，该命令输出

2001:778:200:4280::37
158.129.0.37
2001:778:200:4280::37
61.240.144.64
158.129.0.37
2001:778:200:4280::37
2001:778:200:4001:e076:812f:23e7:7e62
2001:778:200:4280::38
158.129.0.37
222.161.4.149