1、准备好所需要的安装包，http://www.oracle.com/technetwork/database/features/instant-client/index-097480.html这个网址有各种操作系统的客户端

oracle-instantclient-basic-10.2.0.5-1.i386.rpm
oracle-instantclient-devel-10.2.0.5-1.i386.rpm
oracle-instantclient-jdbc-10.2.0.5-1.i386.rpm
oracle-instantclient-sqlplus-10.2.0.5-1.i386.rpm

先安装oracle-instantclient-basic-10.2.0.5-1.i386.rpm，其他依次安装

2、创建用户、组和目录

[root@wxcs-2 oracle]# groupadd oinstall
[root@wxcs-2 oracle]# groupadd dba
[root@wxcs-2 oracle]# useradd -g oinstall -G dba oracle
[root@wxcs-2 oracle]# passwd oracle
Changing password for user oracle.
New UNIX password:
BAD PASSWORD: it is based on a dictionary word
Retype new UNIX password:
passwd: all authentication tokens updated successfully.
[root@wxcs-2 oracle]# mkdir -p /home/oracle/network/admin
[root@wxcs-2 oracle]# chown -R oracle:oinstall /home/oracle
[root@wxcs-2 oracle]# chmod -R 755 /home/oracle

3、将oracle服务器上面的tnsnames.ora拷贝出来，放到/home/oracle/network/admin目录下面。
4、修改环境变量

[oracle@wxcs-2 ~]$ vi .bash_profile

export ORACLE_HOME=/home/oracle
export SQLPATH=/home/oracle/network/admin
export TNS_ADMIN=/home/oracle/network/admin
export NLS_LANG="SIMPLIFIED CHINESE_CHINA.ZHS16GBK"
export LD_LIBRARY_PATH=/usr/lib/oracle/10.2.0.5/client/lib/:/usr/lib/oracle/10.2.0.5/client/lib:$LD_LIBRARY_PA
TH
export PATH=$PATH:$ORACLE_HOME:$LD_LIBRARY_PATH

[oracle@wxcs-2 ~]$ source .bash_profile 环境变量立即生效

5、可以正常连接oracle服务器了

[oracle@wxcs-2 ~]$ sqlplus zhgy/zhgy@192.168.4.36/orcl