本文目的是在CentOS 5.3上安装Oracle 11.2 instant client来访问远端的Oracle 10.2数据库，笔者测试通过，应该也适用于Redhat Linux 5.x

1.下载以下包，但是需要一个oracle的OTN的注册帐号(免费)：

http://download.oracle.com/otn/linux/instantclient/112020/oracle-instantclient11.2-basic-11.2.0.2.0.i386.rpm

http://download.oracle.com/otn/linux/instantclient/112020/oracle-instantclient11.2-sqlplus-11.2.0.2.0.i386.rpm

然后把该两包放到CentOS一个任意目录，比如 ~/tmp，以下过程我都用root帐号/

2.安装该包：

#rpm -ivh ~/tmp/oracle-instantclient11.2-basic-11.2.0.2.0.i386.rpm

#rpm -ivh ~/tmp/oracle-instantclient11.2-sqlplus-11.2.0.2.0.i386.rpm

#vi ~/.bashrc  加入

LD_LIBRARY_PATH=/usr/local/lib:/usr/lib/oracle/11.2/client/lib     #对于64位版本可能是client64

3.测试一下：

#sqlplus /nolog 系统报错

sqlplus: error while loading shared libraries: libsqlplus.so: cannot open shared object file: No such file or directory

4.然后需要：

#vi /etc/ld.so.conf 加入

/usr/lib/oracle/11.2/client/lib/

#/sbin/ldconfig

这样重新运行

# sqlplus /nolog

SQL*Plus: Release 11.2.0.2.0 Production on Tue Nov 8 11:09:58 2011

Copyright (c) 1982, 2010, Oracle. All rights reserved.

SQL>

成功了

5.如需要连接远程oracle，必须配置TNS

#mkdir -p /usr/lib/oracle/11.2/network/admin

#vi /usr/lib/oracle/11.2/network/admin/tnsnames.ora

加入一个Oracle数据库tns信息

PRODB2 =

(DESCRIPTION =

(ADDRESS_LIST =

(ADDRESS = (PROTOCOL = TCP)(HOST = 10.3.103.1)(PORT = 1521))

)

(CONNECT_DATA =

(SERVER=DEDICATED)

(SID = PRODB2)

)

)

同时修改环境变量

#vi ~/.bashrc

LD_LIBRARY_PATH=/usr/local/lib:/usr/lib/oracle/11.2/client/lib

export ORACLE_HOME=/usr/lib/oracle/11.2

export TNS_ADMIN=/usr/lib/oracle/11.2/network/admin

重启一下环境变量，或者用户logout/login一次

#source ~/.bashrc

测试一下

#sqlplus myOracleUsername/password@PRODB2

SQL*Plus: Release 11.2.0.2.0 Production on Tue Nov 8 11:11:56 2011

Copyright (c) 1982, 2010, Oracle. All rights reserved.

Connected to:

Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production

With the Partitioning, Real Application Clusters, OLAP and Data Mining options

SQL> select * from tab;

成功。

6.如果其他用户需要使用sqlplus，需要在该用户的~/.bashrc文件中添加上面提到的3行环境变量

感谢：本文完全参考：http://cysky.blog.51cto.com/211942/563294