Install ELK stack for elk 7.x

elk.sh

#!/bin/bash

# Checking whether user has enough permission to run this script
sudo -n true
if [ $? -ne 0 ]
    then
        echo "This script requires user to have passwordless sudo access"
        exit
fi

dependency_check_deb() {
java -version
if [ $? -ne 0 ]
    then
        # Installing Java 8 if it's not installed
        sudo apt-get install openjdk-8-jre-headless -y
    # Checking if java installed is less than version 7. If yes, installing Java 7. As logstash & Elasticsearch require Java 7 or later.
    elif [ "`java -version 2> /tmp/version && awk '/version/ { gsub(/"/, "", $NF); print ( $NF < 1.8 ) ? "YES" : "NO" }' /tmp/version`" == "YES" ]
        then
            sudo apt-get install openjdk-8-jre-headless -y
fi
}

dependency_check_rpm() {
    java -version
    if [ $? -ne 0 ]
        then
            #Installing Java 8 if it's not installed
            sudo yum install jre-1.8.0-openjdk -y
        # Checking if java installed is less than version 7. If yes, installing Java 8. As logstash & Elasticsearch require Java 7 or later.
        elif [ "`java -version 2> /tmp/version && awk '/version/ { gsub(/"/, "", $NF); print ( $NF < 1.8 ) ? "YES" : "NO" }' /tmp/version`" == "YES" ]
            then
                sudo yum install jre-1.8.0-openjdk -y
    fi
}

debian_elk() {
    # resynchronize the package index files from their sources.
    sudo apt-get update
    # Download and install the public signing key:
    wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
    sudo apt-get install apt-transport-https
    echo "deb https://artifacts.elastic.co/packages/7.x/apt stable main" | sudo tee -a /etc/apt/sources.list.d/elastic-7.x.list
    # Install the Elasticsearch Debian package
    sudo apt-get update && sudo apt-get install -y openjdk-11-jre-headless elasticsearch kibana logstash
    # Starting The Services
    sudo systemctl daemon-reload
    sudo systemctl enable logstash.service
    sudo systemctl start logstash.service
    sudo systemctl enable elasticsearch.service
    sudo systemctl start elasticsearch.service
    sudo systemctl enable kibana.service
    sudo systemctl start kibana.service
}

# Installing ELK Stack
if [ "$(grep -Ei 'debian|buntu|mint' /etc/*release)" ]
    then
        echo " It's a Debian based system"
        dependency_check_deb
        debian_elk


elif [ "$(grep -Ei 'fedora|redhat|centos' /etc/*release)" ]
    then
        echo "It's a RedHat based system."
        dependency_check_rpm
        rpm_elk
else
    echo "This script doesn't support ELK installation on this OS."
fi