问题描述：在操作系统登录数据库时，由于忘记了sys密码，重新修改的sys密码包含@符号，登录时报错，
ORA-12154: TNS:could not resolve the connect identifier specified
要使用在线恢复恢复DG，所以要连接到主库测试tns的连通情况
备库上验证：
[2021/4/23 20:51:13] [oracle@PEKPBSDIHDBP02 dbs]$ sqlplus "sys/elcarO@321qwe"@ORCLDG1 as sysdba
[2021/4/23 20:51:14]
[2021/4/23 20:51:14] SQL*Plus: Release 11.2.0.4.0 Production on Fri Apr 23 20:44:06 2021
[2021/4/23 20:51:14]
[2021/4/23 20:51:14] Copyright (c) 1982, 2013, Oracle. All rights reserved.
[2021/4/23 20:51:14]
[2021/4/23 20:52:34] ERROR:
[2021/4/23 20:52:34] ORA-12154: TNS:could not resolve the connect identifier specified
登录密码包含@，在界面登录需要转义
主库上验证：
[2021/4/23 20:55:11] [oracle@PEKPBSDIHDBP02 dbs]$ sqlplus sys/\"elcarO@321qwe\"@orcl_stb as sysdba
[2021/4/23 20:55:11]
[2021/4/23 20:55:11] SQL*Plus: Release 11.2.0.4.0 Production on Fri Apr 23 20:48:03 2021
[2021/4/23 20:55:11]
[2021/4/23 20:55:11] Copyright (c) 1982, 2013, Oracle. All rights reserved.
[2021/4/23 20:55:11]
[2021/4/23 20:55:11]
[2021/4/23 20:55:11] Connected to:
[2021/4/23 20:55:11] Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
[2021/4/23 20:55:11] With the Partitioning, OLAP, Data Mining and Real Application Testing options
转义写法：sqlplus sys/\"密码\"@tnsname
ORA-12154: TNS:could not resolve the connect identifier specified--sys密码包含@符号
原文：https://www.cnblogs.com/houzhiheng/p/14703195.html