[Linux] grep

• grep을 통해 특정 단어에 해당하는 내용 추출

seho4815@linux-up-skill:/var/log$ cat auth.log | grep "authenticating"
Jan 23 06:01:51 linux-up-skill sshd[3276]: Disconnected from authenticating user root 221.181.185.220 port 56537 [preauth]
Jan 23 06:10:39 linux-up-skill sshd[3502]: Disconnected from authenticating user root 221.181.185.148 port 21607 [preauth]
Jan 23 06:19:41 linux-up-skill sshd[3614]: Disconnected from authenticating user root 221.181.185.220 port 58425 [preauth]
Jan 23 06:28:28 linux-up-skill sshd[3781]: Disconnected from authenticating user root 221.181.185.220 port 20040 [preauth]
Jan 23 06:37:10 linux-up-skill sshd[3889]: Disconnected from authenticating user root 221.181.185.220 port 17097 [preauth]
Jan 23 06:45:55 linux-up-skill sshd[3984]: Disconnected from authenticating user root 221.181.185.220 port 14590 [preauth]
Jan 23 07:02:01 linux-up-skill sshd[4164]: Disconnected from authenticating user root 222.187.222.53 port 60394 [preauth]
Jan 23 07:03:25 linux-up-skill sshd[4234]: Disconnected from authenticating user root 221.181.185.198 port 45795 [preauth]
Jan 23 07:08:08 linux-up-skill sshd[4643]: Disconnecting authenticating user root 75.164.151.45 port 56902: Too many authentication f
ailures [preauth]
Jan 23 07:08:12 linux-up-skill sshd[4645]: Disconnecting authenticating user root 75.164.151.45 port 57038: Too many authentication f
ailures [preauth]
Jan 23 07:08:18 linux-up-skill sshd[4647]: Disconnected from authenticating user root 75.164.151.45 port 57150 [preauth]
Jan 23 07:12:25 linux-up-skill sshd[4806]: Disconnected from authenticating user root 221.181.185.220 port 34385 [preauth]
Jan 23 07:30:13 linux-up-skill sshd[5089]: Disconnected from authenticating user root 221.181.185.220 port 19304 [preauth]
Jan 23 07:44:45 linux-up-skill sshd[6345]: Connection closed by authenticating user root 27.70.134.169 port 58118 [preauth]
Jan 23 07:47:47 linux-up-skill sshd[6385]: Disconnected from authenticating user root 221.181.185.148 port 54817 [preauth]
Jan 23 07:52:16 linux-up-skill sshd[6471]: Connection closed by authenticating user root 171.240.195.82 port 36888 [preauth]
Jan 23 07:52:34 linux-up-skill sshd[6473]: Disconnected from authenticating user root 106.75.146.217 port 53458 [preauth]
Jan 23 07:53:34 linux-up-skill sshd[6489]: Connection closed by authenticating user root 27.70.134.169 port 60284 [preauth]
Jan 23 07:53:55 linux-up-skill sshd[6503]: Connection closed by authenticating user root 27.70.134.169 port 56050 [preauth]
Jan 23 07:56:40 linux-up-skill sshd[6533]: Disconnected from authenticating user root 221.181.185.148 port 13011 [preauth]
Jan 23 08:05:29 linux-up-skill sshd[6660]: Disconnected from authenticating user root 221.181.185.135 port 44311 [preauth]

결과를 보면 authenticating을 포함한 내용만 출력되는 것을 확인할 수 있습니다.

 

 

• grep을 통해 특정 단어 포함된 내용 제외

cat [파일명] | grep -v "제외하고자 하는 문자"

 

 

• grep 중첩

seho4815@linux-up-skill:/var/log$ grep "authenticating" /var/log/auth.log |  grep  "root"
Jan 23 06:01:51 linux-up-skill sshd[3276]: Disconnected from authenticating user root 221.181.185.220 port 56537 [preauth]
Jan 23 06:10:39 linux-up-skill sshd[3502]: Disconnected from authenticating user root 221.181.185.148 port 21607 [preauth]
Jan 23 06:19:41 linux-up-skill sshd[3614]: Disconnected from authenticating user root 221.181.185.220 port 58425 [preauth]
Jan 23 06:28:28 linux-up-skill sshd[3781]: Disconnected from authenticating user root 221.181.185.220 port 20040 [preauth]
Jan 23 06:37:10 linux-up-skill sshd[3889]: Disconnected from authenticating user root 221.181.185.220 port 17097 [preauth]
Jan 23 06:45:55 linux-up-skill sshd[3984]: Disconnected from authenticating user root 221.181.185.220 port 14590 [preauth]
Jan 23 07:02:01 linux-up-skill sshd[4164]: Disconnected from authenticating user root 222.187.222.53 port 60394 [preauth]
Jan 23 07:03:25 linux-up-skill sshd[4234]: Disconnected from authenticating user root 221.181.185.198 port 45795 [preauth]
Jan 23 07:08:08 linux-up-skill sshd[4643]: Disconnecting authenticating user root 75.164.151.45 port 56902: Too many authentication f
ailures [preauth]
Jan 23 07:08:12 linux-up-skill sshd[4645]: Disconnecting authenticating user root 75.164.151.45 port 57038: Too many authentication f
ailures [preauth]
Jan 23 07:08:18 linux-up-skill sshd[4647]: Disconnected from authenticating user root 75.164.151.45 port 57150 [preauth]
Jan 23 07:12:25 linux-up-skill sshd[4806]: Disconnected from authenticating user root 221.181.185.220 port 34385 [preauth]
Jan 23 07:30:13 linux-up-skill sshd[5089]: Disconnected from authenticating user root 221.181.185.220 port 19304 [preauth]
Jan 23 07:44:45 linux-up-skill sshd[6345]: Connection closed by authenticating user root 27.70.134.169 port 58118 [preauth]
Jan 23 07:47:47 linux-up-skill sshd[6385]: Disconnected from authenticating user root 221.181.185.148 port 54817 [preauth]
Jan 23 07:52:16 linux-up-skill sshd[6471]: Connection closed by authenticating user root 171.240.195.82 port 36888 [preauth]
Jan 23 07:52:34 linux-up-skill sshd[6473]: Disconnected from authenticating user root 106.75.146.217 port 53458 [preauth]
Jan 23 07:53:34 linux-up-skill sshd[6489]: Connection closed by authenticating user root 27.70.134.169 port 60284 [preauth]
Jan 23 07:53:55 linux-up-skill sshd[6503]: Connection closed by authenticating user root 27.70.134.169 port 56050 [preauth]
Jan 23 07:56:40 linux-up-skill sshd[6533]: Disconnected from authenticating user root 221.181.185.148 port 13011 [preauth]
Jan 23 08:05:29 linux-up-skill sshd[6660]: Disconnected from authenticating user root 221.181.185.135 port 44311 [preauth]
Jan 23 08:14:02 linux-up-skill sshd[6779]: Disconnected from authenticating user root 221.181.185.135 port 19777 [preauth]