Oracle中su切换进去sqlplus登录失败的问题处理

生产环境的Oracle数据库突然登录不上去了，rlwrap生产环境的oracle数据库突然登录不上去了，rlwrap sqlplus / as sysdba报错如

问题描述：
生产环境的Oracle数据库突然登录不上去了，rlwrap生产环境的oracle数据库突然登录不上去了，rlwrap sqlplus "/ as sysdba"报错如下：rlwrap
[oracle@localhost root]$ rlwrap sqlplus "/ as sysdba"
rlwrap: warning: your $TERM is 'xterm' but rlwrap couldn't find it in the terminfo database. Expect some problems.
rlwrap: Cannot execute sqlplus: Permission denied
[oracle@localhost root]$ sqlplus "/ as sysdba"
bash: sqlplus: command not found
[oracle@localhost root]$

1，oracle登录报错
[oracle@localhost root]$ rlwrap sqlplus "/ as sysdba"
Error 6 initializing SQL*Plus
SP2-0667: Message file sp1.msb not found
SP2-0750: You may need to set ORACLE_HOME to your Oracle software directory
[oracle@localhost root]$
[oracle@localhost root]$

2，查看ORACLE_HOME变量，为空值
[oracle@localhost root]$ echo $ORACLE_HOME

[oracle@localhost root]$

3，在/etc/profile设置ORACLE_HOME变量
[root@localhost ~]# vim /etc/profile
export ORACLE_HOME=/opt/oracle/app/oracle/product/11.2.0/dbhome_1

[root@localhost ~]# source /etc/profile
[root@localhost ~]# su oracle
[oracle@localhost root]$
[oracle@localhost root]$ echo $ORACLE_HOME
/oracle/app/oracle/product/11.2.0/dbhome_1/
[oracle@localhost root]$

4，ORACLE_HOME环境变量有值了，再去用sqlplus登录一下，试试看
[oracle@localhost root]$ rlwrap sqlplus "/ as sysdba"
rlwrap: warning: your $TERM is 'xterm' but rlwrap couldn't find it in the terminfo database. Expect some problems.
rlwrap: Cannot execute sqlplus: Permission denied
[oracle@localhost root]$

5，做一下sqlplus的软连接
[oracle@localhost root]$ exit
exit
[root@localhost ~]# ln -s $ORACLE_HOME/bin/sqlplus /usr/bin
[root@localhost ~]# su oracle
[oracle@localhost root]$ sqlplus "/ as sysdba"

SQL*Plus: Release 11.2.0.1.0 Production on Fri Jan 16 10:19:39 2015

Copyright (c) 1982, 2009, Oracle. All rights reserved.

ERROR:
ORA-12162: TNS:net service name is incorrectly specified

Enter user-name:
ERROR:
ORA-12162: TNS:net service name is incorrectly specified

Enter user-name:
ERROR:
ORA-12162: TNS:net service name is incorrectly specified

SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus
[oracle@localhost root]$
[oracle@localhost root]$ echo $ORACLE_SID

[oracle@localhost root]$
系统环境变量里面没有ORACLE_SID

6，设置ORACLE_SID
[oracle@localhost root]$ exit
exit
[root@localhost ~]# vim /etc/profile
export ORACLE_HOME=/oracle/app/oracle/product/11.2.0/dbhome_1/
export ORACLE_SID=pxxerxxs
[root@localhost ~]# source /etc/profile

[oracle@localhost root]$ exit
exit
[root@localhost ~]# vim /etc/profile
[root@localhost ~]# source /etc/profile
[root@localhost ~]# su oracle
[oracle@localhost root]$ rlwrap sqlplus "/ as sysdba"
rlwrap: warning: your $TERM is 'xterm' but rlwrap couldn't find it in the terminfo database. Expect some problems.
SQL*Plus: Release 11.2.0.1.0 Production on Fri Jan 16 10:25:33 2015

Copyright (c) 1982, 2009, Oracle. All rights reserved.

Connected to an idle instance.

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7，去oracle用户下查看系统变量
[oracle@localhost root]$ cat ~/.bash_profile
# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
. ~/.bashrc
fi

# User specific environment and startup programs

PATH=$PATH:$HOME/bin

export PATH