Fast installation for oracle db under redhat linux 4 update 3

Question

dear sirs...
i know little about linux, however, i create a simple script that will preform pre-installation operations for linux 4 update 3. it will update the files, create oracle user, and so on. you will find its source. if possible i hope someone can upgrade this script such that there it will check the OS packages, and stop the changes if any of the packages is missing.
thanks for any help and best regards.
notes:
1- to use this script, type the text in linux gedit. save it in a file and put the file in a safe place so that every time you want to install the db, you can find it ready.
2- do not use notepad to create the file, it will not work.
3- before you run the script, be sure that all packages needed by the db exists.
4- the script assumes that you have just installed linux for running the database only.
5- to run the script in linux , login as root user, and type . scriptfilename
6- the script should be executed only once.
/usr/sbin/groupadd oinstall
/usr/sbin/groupadd dba
/usr/sbin/useradd -m -g oinstall -G dba oracle
passwd oracle
mkdir -p /home/oracle
chown -R oracle:oinstall /home/oracle
chmod -R 775 /home/oracle
cat >> /etc/sysctl.conf <<EOF
# the following lines are added by a script
kernel.shmall = 2097152
kernel.shmmax = 536870912
kernel.shmmni = 4096
kernel.sem = 250 32000 100 128
fs.file-max = 65536
net.ipv4.ip_local_port_range = 1024 65000
net.core.rmem_default = 262144
net.core.wmem_default = 262144
net.core.rmem_max = 262144
net.core.wmem_max = 262144
EOF
/sbin/sysctl -p
cat >> /etc/security/limits.conf <<EOF
# the following lines are added by a script
oracle soft nproc 2047
oracle hard nproc 16384
oracle soft nofile 1024
oracle hard nofile 65536
EOF
cat >> /etc/pam.d/login <<EOF
# the following lines are added by a script
session required /lib/security/pam_limits.so
EOF
cat >> /etc/profile <<EOF
# the following lines are added by a script
if [ \$USER = "oracle" ]; then
if [ \$SHELL = "/bin/ksh" ]; then
ulimit -p 16384
ulimit -n 65536
else
ulimit -u 16384 -n 65536
fi
umask 022
fi
EOF
cat >> /etc/csh.login <<EOF
# the following lines are added by a script
if ( \$USER == "oracle" ) then
limit maxproc 16384
limit descriptors 65536
umask 022
endif
EOF

Answer 1

Nice.
A fair chunk of additional work would go into this to ensure that existing settings are not clobbered, but it should be OK on a new install of Linux.
Why not require that they use the DVD (so you have all RPMs on one media), cd to the RPMS directory and simply 'rpm -i' all the prereq packages? Then you don't need to 'rpm -q' and inspect the status.