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）：
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