Post-installation Scripts:CentOS 6

#!/bin/sh
###########################################################################
#          Remplace "YOUR_EMAIL_ADDRESS" by your email address name       #
###########################################################################
Email='YOUR_EMAIL_ADDRESS'
DNS='8.8.8.8'

IP=`grep IPADDR /etc/sysconfig/network-scripts/ifcfg-eth0 | tr -cd "0-9\."`
HOST=`host $IP $DNS| tail -1 | awk '{print $5}' | awk -F'.' '{print $1"."$2"."$3}'`

TestIP=`echo $IP | egrep "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$"`
TestHost=`echo $HOST | egrep '(ovh|kimsufi)'`

cat > /root/.ssh/authorized_keys2 << EOF
from="213.186.50.100" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAt3XaIhEoRK5sEKm6wtYyazLOx3w+Yv9+bpfEvLftHr2hxZ2TY2A655iwMbgvhHqsMuGEjK9yGkZIQbUgB6HvOgOWOwJSX6Gc9Ac7GuH11xSU8tHDuTQot6fVtgcm2Y/VUFi65Knz9rLHz7h/Zy29ek+UYav5T7juhBIuk57cDxs=
from="::ffff:213.186.50.100" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAt3XaIhEoRK5sEKm6wtYyazLOx3w+Yv9+bpfEvLftHr2hxZ2TY2A655iwMbgvhHqsMuGEjK9yGkZIQbUgB6HvOgOWOwJSX6Gc9Ac7GuH11xSU8tHDuTQot6fVtgcm2Y/VUFi65Knz9rLHz7h/Zy29ek+UYav5T7juhBIuk57cDxs=
EOF

apply(){

hostname $HOST

cat > /etc/resolv.conf << EOF
nameserver      213.186.33.99
nameserver      8.8.8.8
nameserver      8.8.4.4
EOF

sed -ri s/"(ns|ks)[0-9].*(ovh.net|kimsufi.com)"/$HOST/g /etc/issue
sed -ri s/"(ns|ks)[0-9].*(ovh.net|kimsufi.com)"/$HOST/g /etc/motd
sed -ri s/"HOSTNAME=.*"/"HOSTNAME=$HOST"/g /etc/sysconfig/network
sed -ri s/"$IP.*"/"$IP\t$HOST"/g /etc/hosts

sed -ri s/" root@.*"//g /etc/ssh/ssh_host_dsa_key.pub
sed -ri s/" root@.*"//g /etc/ssh/ssh_host_key.pub
sed -ri s/" root@.*"//g /etc/ssh/ssh_host_rsa_key.pub


>/var/log/dmesg
>/var/log/messages
rm -f /var/log/maillog*
rm -f /var/log/install_rtm.log
rm -f /usr/local/rtm/scripts/daily/release.sh
rm -f /var/spool/mail/root

/etc/init.d/rsyslog restart

rm -f /root/.bash_history
history -c

}

verify(){

grepovh=`egrep -R '(ovh|kimsufi)' /etc/ 2>/dev/null| egrep -v '(/etc/ssh/ssh_host_key|/etc/services|/etc/pki/|/etc/aliases|/etc/ssl/certs/|Binary file)'`

if [ -n "$grepovh" ]
then
		pass=`head -c 200 /dev/urandom | tr -cd '0-9a-zA-Z' | head -c 8`
		echo $pass | /usr/bin/passwd --stdin root
		echo "
		Erreur lors de l'installation du serveur $IP
		Hostname : $HOST
		Mot de pass : $pass
		" |mail -s "ERREUR INSTALLATION" $Email
		rm -f /root/.p
		exit 255
else
		exit 0
fi
}

if [ -n $TestIP ] && [ -z $TestHost ]
then
		apply
		verify
else
		pass=`head -c 200 /dev/urandom | tr -cd '0-9a-zA-Z' | head -c 8`
		echo $pass | /usr/bin/passwd --stdin root
		echo "
		Erreur lors de l'installation du serveur $IP
		Hostname : $HOST
		Mot de pass : $pass
		" |mail -s "ERREUR INSTALLATION" $Email
		rm -f /root/.p
		exit 254
fi