Linux下安装Oracle系统最好是1G内存，2G的swap空间，硬盘至少需要4.5G空间。

至少环境在Linux Server release 5.3以上

如果是Linux Server release 5.1，改装oracle10.2g吧

一、查看Linux版本

[root@localhost ~]# cat /etc/issue
Red Hat Enterprise Linux Server release 5.5 (Tikanga)

[root@localhost ~]# cat /etc/RedHat-release 
Red Hat Enterprise Linux Server release 5.5 (Tikanga)

二、到oracle官方网站下载对应版本的oracle，我下的是oracle  for linux X86
 http://www.oracle.com/technetwork/database/enterprise-edition/downloads/index.html
 

三、在linux下创建oracle用户，以及管理组
 3.1 以root用户登录linux，执行以下命令

[root@localhost ~]#/usr/sbin/groupadd dba
[root@localhost ~]#/usr/sbin/groupadd oper
[root@localhost ~]#/usr/sbin/groupadd oinstall

小技巧：
 查看Linux用户组命令：

[root@localhost ~]# cat /etc/group

3.2 添加oracle用户

[root@localhost ~]#useradd oracle
[root@localhost ~]#/usr/sbin/usermod -g oinstall -G dba oracle
[root@localhost ~]#passwd oracle
Changing password for user oracle.
New UNIX password: oracle
BAD PASSWORD: it is based on a dictionary word
Retype new UNIX password: oracle
passwd: all authentication tokens updated successfully.

3.3 预先创建安装目录
[root@localhost ~]#mkdir -p /opt/oracle/product
[root@localhost ~]#mkdir -p /opt/oracle/product/OraHome
[root@localhost ~]#mkdir -p /opt/oraInventory
[root@localhost ~]#mkdir -p /opt/oracle/oradata
[root@localhost ~]#mkdir -p /var/opt/oracle

3.4 设置目录的所有者所属组和权限

[root@localhost ~]#chown -R oracle.oinstall /opt/oracle
[root@localhost ~]#chown -R oracle.oinstall /opt/oracle/oradata
[root@localhost ~]#chown -R oracle.oinstall /opt/oracle/product/OraHome
[root@localhost ~]#chown -R oracle.dba /opt/oraInventory
[root@localhost ~]#chown oracle.dba /var/opt/oracle
[root@localhost ~]#chmod -R 775 /opt/oracle
[root@localhost ~]#chmod -R 755 /var/opt/oracle

3.5 设置用户oracle的环境变量

#su - oracle
[oracle@localhost ~]$ vi /home/oracle/.bash_profile

在文件底部添加

export ORACLE_BASE=/opt/oracle
export ORACLE_HOME=$ORACLE_BASE/product/OraHome
export ORACLE_SID=orcl
export ORACLE_OWNER=oracle
export ORACLE_TERM=vt100
export PATH=$PATH:$ORACLE_HOME/bin:$HOME/bin
export PATH=$ORACLE_HOME/bin:$ORACLE_HOME/Apache/Apache/bin:$PATH
LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib:/usr/local/lib
export LD_LIBRARY_PATH
CLASSPATH=$ORACLE_HOME/JRE:$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
CLASSPATH=$CLASSPATH:$ORACLE_HOME/network/jlib
export CLASSPATH
PATH=$PATH:/usr/sbin; export PATH
PATH=$PATH:/usr/bin; export PATH

--执行以下命令让配置马上生效或以oracle用户登录使设置生效

[oracle@localhost ~]$ source $HOME/.bash_profile