Step 1: download oracle 12c in oracle website

Step 2: create group and user install oracle

#groupadd oinstall
#groupadd dba
#groupadd oper
#useradd -G dba,oper -g oinstall oracle
#passwd oracle

Step 3: create folder install oracle

#mkdir -p /u01/app/oracle/product/12.1/db_1
#mkdir -p /u01/setup
#chown -R oracle:oinstall /u01
#chmod -R 775 /u01

Step 4: Set parameter

#vi /etc/sysctl.conf
add the following lines
fs.file-max = 6815744
kernel.sem = 250 32000 100 128
kernel.shmmni = 4096
kernel.shmall = 1073741824
kernel.shmmax = 4398046511104
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 1048576
fs.aio-max-nr = 1048576
net.ipv4.ip_local_port_range = 9000 65500
#/sbin/sysctl -p
#vi /etc/security/limits.conf
add the following lines
oracle soft nofile 1024
oracle hard nofile 65536
oracle soft nproc 16384
oracle hard nproc 16384
oracle soft stack 10240
oracle hard stack 32768

Step 5: Install the following packages if they are not already present.

yum install binutils -y
yum install compat-libcap1 -y
yum install compat-libstdc++-33 -y
yum install compat-libstdc++-33.i686 -y
yum install gcc -y
yum install gcc-c++ -y
yum install glibc -y
yum install glibc.i686 -y
yum install glibc-devel -y
yum install glibc-devel.i686 -y
yum install ksh -y
yum install libgcc -y
yum install libgcc.i686 -y
yum install libstdc++ -y
yum install libstdc++.i686 -y
yum install libstdc++-devel -y
yum install libstdc++-devel.i686 -y
yum install libaio -y
yum install libaio.i686 -y
yum install libaio-devel -y
yum install libXext -y
yum install libXext.i686 -y
yum install libXtst -y
yum install libXtst.i686 -y
yum install libX11 -y
yum install libX11.i686 -y
yum install libXau -y
yum install libXau.i686 -y
yum install libxcb -y
yum install libxcb.i686 -y
yum install libXi -y
yum install libXi.i686 -y
yum install make -y
yum install sysstat -y
yum install unixODBC -y
yum install unixODBC-devel -y
now, i installed all packages 

Step 6: add in hosts file

#vi /etc/hosts
add the following lines oracle.test
oracle.test is hostname and is ip address

Step 7: Set environmental variable for user ORACLE

#su - oracle
$ cd ~
$ vi .bash_profile
add the following lines
# Oracle Settings
export TMP=/tmp
export TMPDIR=$TMP
export ORACLE_HOSTNAME=oracle.test
export ORACLE_UNQNAME=dbtest
export ORACLE_BASE=/u01/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/12.1/db_1
export ORACLE_SID=dbtest
export PATH=/usr/sbin:$PATH
export LD_LIBRARY_PATH=$ORACLE_HOME/lib:/lib:/usr/lib
export CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib

Step 8: Upload files to server using user Oracle

Step 9: Unzip files


Step 10: Install oracle DB

$xhost +
$cd /u01/setup/database
now, install ORACLE DATABSE using DBCA