Month: June 2020

Making the following update to your Nginx .conf file will prevent your website from being accessed directly by it’s IP address

You’ll need to create a new server block and configure it such that any requests to the servers IP address will instead be redirected to the domain name.

server {
    listen 80;
    # Listen to your server ip address
    # Redirect all traffic comming from your-server-ip to your domain
    return 301 $scheme://$request_uri;

Now, when a request is made to it will be redirected to

I noticed that on my CentOS 6 box, I was still running nginx 1.0.15. I wanted to upgrade to nginx 1.10.1. However, when I ran sudo yum update nginx, it showed that there were no Packages marked for Update.

Luckily, getting the latest version through Yum is straight-forward and only requires adding a new repo. First, create a new file, nginx.repo, in the yum repo directory.

$ vim /etc/yum.repos.d/nginx.repo

Next, give it the following contents:

name=nginx repo  

Save the file, then shut down the nginx service (unnecessary if nginx wasn’t on the system previously)

$ sudo service nginx stop  

Now, run the yum update command again (or install if nginx wasn’t on the system previously)

$ sudo yum update nginx

It should now let you update to the latest version! As soon as you install the new version, start nginx back up.

$ sudo service nginx start

The way to reset the root password on centos7 is totally different to Centos 6. Let me show you how to reset root password in CentOS 7.

1 – In the boot grub menu select option to edit.


2 – Select Option to edit (e).


3 – Go to the line of Linux 16 and change ro with rw init=/sysroot/bin/sh.


4 – Now press Control+x to start on single user mode.


5 – Now access the system with this command.

chroot /sysroot

6 – Reset the password.

passwd root

7 – Update selinux information

touch /.autorelabel

8 – Exit chroot


9 – Reboot your system


That’s it. Enjoy.

Step 1 — Installing Nginx

In order to display web pages to our site visitors, we are going to employ Nginx, a high-performance web server. To get the latest Nginx version, we’ll first install the EPEL repository, which contains additional software for the CentOS 7 operating system.

To add the CentOS 7 EPEL repository, run the following command:

sudo yum install epel-release

Since we are using a sudo command, these operations get executed with root privileges. It will ask you for your regular user’s password to verify that you have permission to run commands with root privileges. You’ll also be prompted to confirm installation, so press Y to proceed.

Now that the EPEL repository is installed on your server, install Nginx using the following yum command:

sudo yum install nginx

Once the installation is finished, start the Nginx service with:

sudo systemctl start nginx

You can do a spot check right away to verify that everything went as planned by visiting your server’s public IP address in your web browser (see the note under the next heading to find out what your public IP address is if you do not have this information already):

Open in a web browser:http://server_domain_name_or_IP/

You will see the default CentOS 7 Nginx web page, which is there for informational and testing purposes. It should look something like this:

CentOS 7 Nginx Default

If you see this page, then your web server is now correctly installed.

To enable Nginx to start on boot, run the following command:

sudo systemctl enable nginx

How To Find Your Server’s Public IP Address

If you do not know what your server’s public IP address is, there are a number of ways you can find it. Usually, this is the address you use to connect to your server through SSH.

From the command line, you can find this a few ways. First, you can use the iproute2 tools to get your address by typing this:

ip addr show eth0 | grep inet | awk '{ print $2; }' | sed 's/\/.*$//'

This will give you one or two lines back. They are both correct addresses, but your computer may only be able to use one of them, so feel free to try each one.

An alternative method is to use an outside party to tell you how it sees your server. You can do this by asking a specific server what your IP address is:


Regardless of the method you use to get your IP address, you can type it into your web browser’s address bar to get to your server.

Step 2 — Installing MariaDB

Now that we have our web server up and running, it is time to install MariaDB, a MySQL drop-in replacement. MariaDB is a community-developed fork of the MySQL relational database management system.

Again, we can use yum to acquire and install our software. This time, we’ll also install some other helper packages that will assist us in getting our components to communicate with each other:

sudo yum install mariadb-server mariadb

When the installation is complete, we need to start MariaDB with the following command:

sudo systemctl start mariadb

Now that our MariaDB database is running, we want to run a security script that will remove some dangerous defaults and lock down access to our database. Start the interactive script by running:

sudo mysql_secure_installation

The prompt will ask you for your current root MariaDB password. Since you just installed MariaDB, you most likely won’t have one, so leave it blank by pressing enter. Then the prompt will ask you if you want to set a root password. Go ahead and enter Y, and follow the instructions:

mysql_secure_installation prompts:Enter current password for root (enter for none): 
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

Set root password? [Y/n] y
New password: 
Re-enter new password: 
Password updated successfully!
Reloading privilege tables..
 ... Success!

For the rest of the questions, you should hit the “ENTER” key through each prompt to accept the default values. This will remove some sample users and databases, disable remote root logins, and load these new rules so that MySQL immediately respects the changes we have made.

The last thing you will want to do is enable MariaDB to start on boot. Use the following command to do so:

sudo systemctl enable mariadb

At this point, your database system is now set up and we can move on.

Step 3 — Installing PHP

PHP is the component of our setup that will process code to display dynamic content. It can run scripts, connect to our MySQL databases to get information, and hand the processed content over to our web server to display.

The PHP version available by default within CentOS 7 servers is outdated, and for that reason, we’ll need to install a third-party package repository in order to obtain PHP 7+ and get it installed on your CentOS 7 server. Remi is a popular package repository providing the most up-to-date PHP releases for CentOS servers.

To install the Remi repository for CentOS 7, run:

sudo yum install

After the installation is done, you’ll need to run a command to enable the repository containing your preferred version of PHP. To check which PHP 7+ releases are available in the Remi repository, run:

yum --disablerepo="*" --enablerepo="remi-safe" list php[7-9][0-9].x86_64

You’ll see output like this:

OutputLoaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * remi-safe:
Available Packages
php70.x86_64                                              2.0-1.el7.remi                                       remi-safe
php71.x86_64                                              2.0-1.el7.remi                                       remi-safe
php72.x86_64                                              2.0-1.el7.remi                                       remi-safe
php73.x86_64                                              2.0-1.el7.remi                                       remi-safe
php74.x86_64                                              1.0-3.el7.remi                                       remi-safe
php80.x86_64                                              1.0-3.el7.remi                                       remi-safe

In this guide, we’ll install PHP 7.4, which is currently the most updated stable version of PHP. To enable the correct Remi package to get PHP 7.4 installed, run:

sudo yum-config-manager --enable remi-php74

Now we can proceed to use yum for installing PHP as usual. The following command will install all the required packages to get PHP 7.4 set up within Nginx and allow it to connect to MySQL-based databases:

sudo yum install php php-mysqlnd php-fpm

To confirm that PHP is available as your chosen version, run:

php --version

You’ll see output like this:

OutputPHP 7.4.5 (cli) (built: Apr 14 2020 12:54:33) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies

PHP is now successfully installed on your system. Next, we need to make a few adjustments to the default configuration. To facilitate editing files on CentOS, we’ll first install nano, a more user-friendly text editor than vi:

sudo yum install nano

Open the /etc/php-fpm.d/www.conf configuration file using nano or your editor of choice:

sudo nano /etc/php-fpm.d/www.conf

Now look for the user and group directives. If you are using nano, you can hit CTRL+W to search for these terms inside the open file. /etc/php-fpm.d/www.conf

; Unix user/group of processes
; Note: The user is mandatory. If the group is not set, the default user's group
;       will be used.
; RPM: apache user chosen to provide access to the same directories as httpd
user = apache
; RPM: Keep a group allowed to write in log dir.
group = apache

You’ll notice that both the user and group variables are set to apache. We need to change these to nginx: /etc/php-fpm.d/www.conf

; RPM: apache user chosen to provide access to the same directories as httpd
user = nginx
; RPM: Keep a group allowed to write in log dir.
group = nginx

Next, locate the listen directive. By default, php-fpm will listen on a specific host and port over TCP. We want to change this setting so it listens on a local socket file, since this improves the overall performance of the server.
Change the line containing the listen directive to the following: /etc/php-fpm.d/www.conf

listen = /var/run/php-fpm/php-fpm.sock;

Finally, we’ll need to change the owner and group settings for the socket file we just defined within the listen directive. Locate the listen.owner, and listen.mode directives. These lines are commented out by default. Uncomment them by removing the preceding ; sign at the beginning of the line. Then, change the owner and group to nginx: /etc/php-fpm.d/www.conf

listen.owner = nginx = nginx
listen.mode = 0660

Save and close the file when you’re done editing. If you are using nano, do so by pressing CTRL + X, then Y and ENTER.

To enable and start the php-fpm service, run:

sudo systemctl start php-fpm

Your PHP environment is now ready. Next, we’ll configure Nginx so that it sends all requests for PHP scripts to be processed by php-fpm.

Step 4 — Configuring Nginx to Process PHP Pages

Now, we have all of the required components installed. The only configuration change we still need to do is tell Nginx to use our PHP processor for dynamic content.

Nginx has a dedicated directory where we can define each hosted website as a separate configuration file, using a server block. This is similar to Apache’s virtual hosts.

With the default installation, however, this directory is empty. We’ll create a new file to serve as the default PHP website on this server, which will override the default server block defined in the /etc/nginx/nginx.conf file.

First, open a new file in the /etc/nginx/conf.d directory:

sudo nano /etc/nginx/conf.d/default.conf

Copy the following PHP server definition block to your configuration file, and don’t forget to replace the server_name directive so that it points to your server’s domain name or IP address: /etc/nginx/conf.d/default.conf

server {
    listen       80;
    server_name  server_domain_or_IP;

    root   /usr/share/nginx/html;
    index index.php index.html index.htm;

    location / {
        try_files $uri $uri/ =404;
    error_page 404 /404.html;
    error_page 500 502 503 504 /50x.html;

    location = /50x.html {
        root /usr/share/nginx/html;

    location ~ \.php$ {
        try_files $uri =404;
        fastcgi_pass unix:/var/run/php-fpm/php-fpm.sock;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;

Save and close the file when you’re done.

Next, restart Nginx to apply the changes:

sudo systemctl restart nginx

Your web server is now fully set up. In the next step, we’ll test the PHP integration to Nginx.

Step 5 — Testing PHP Processing on your Web Server

Now that your web server is set up, we can create a test PHP script to make sure Nginx is correctly handling .php scripts with the help of php-fpm.

Before creating our script, we’ll make a change to the default ownership settings on Nginx’s document root, so that our regular sudo user is able to create files in that location.

The following command will change the ownership of the default Nginx document root to a user and group called sammy, so be sure to replace the highlighted username and group in this command to reflect your system’s username and group.

sudo chown -R sammy.sammy /usr/share/nginx/html/

We’ll now create a test PHP page to make sure the web server works as expected.

Create a new PHP file called info.php at the /usr/share/nginx/html directory:

nano /usr/share/nginx/html/info.php

The following PHP code will display information about the current PHP environment running on the server: /usr/share/nginx/html/info.php



When you are finished, save and close the file.

Now we can test whether our web server can correctly display content generated by a PHP script. Go to your browser and access your server hostname or IP address, followed by /info.php:


You’ll see a page similar to this:

CentOS 7 PHP 7.4 info

After checking the relevant information about your PHP server through that page, it’s best to remove the file you created as it contains sensitive information about your PHP environment and your CentOS server. You can use rm to remove that file:

rm /usr/share/nginx/html/info.php

You can always regenerate this file if you need it later.

Find Files and Directories in CentOS

The find command helps you locate files and folders on your hard disk. There are additional parameters that can be passed to the command that help you find files and folders in multiple ways. Find by filename, modified time, find files and folders.

Basic syntax

find /path/to/search -option1 -option2

Find a file by name

Search your entire system from the root folder “/” for a file named “”, which is presumably a shell script.

find / -name

Find empty files

Lets find empty files in /tmp/

find /tmp -type f -empty

Find empty directories/folders

Lets find empty directories in /tmp/

find /tmp -type d -empty

Find files not modified for a set duration

Files under /var/log that haven’t been written to or otherwise modified in a week or more.

find /var/log -mtime +7

Find files to delete

Now lets find files under /var/log which have not been modified for a week and delete them.

find /var/log -mtime +7 -exec rm -f {} \;


This articles describe on installing the paravirtualized drivers on a linux operating systems like centos, redhat, ubuntu


1. Insert the XenTools ISO in the DVD drive of the Linux VM
2. Mount the DVD drive to /mnt using : “mount /dev/xvdd /mnt”
User-added image
It says , mount : block device /dev/xvdd is write-protected, mounting read-only 

The location of the tools could be /dev/cdrom in some linux flavours.
So, if  /dev/xvdd is not working then try “mount /dev/cdrom /mnt”

3. change the directory to /mnt using “cd /mnt” and then list the contents using “ls” and then  Change the directory to /Linux using “cd Linux/” . Use “ls” to list the contents again.

User-added image
4. Use ./ to install the XenTools 
Continue? [y/n] y

User-added image
5. XenTools should show optimized 

User-added image

6. Reboot the VM once. 


mysqldump db_name table_name > table_name.sql

Dumping from a remote database

mysqldump -u <db_username> -h <db_host> -p db_name table_name > table_name.sql


mysql -u <user_name> -p db_name
mysql> source <full_path>/table_name.sql

or in one line

mysql -u username -p db_name < /path/to/table_name.sql

Dump and restore a single table from a compressed (.sql.gz) format


mysqldump db_name table_name | gzip > table_name.sql.gz


gunzip < table_name.sql.gz | mysql -u username -p db_name