Harsha  Shirali

Harsha Shirali


Install LAMP Stack on CentOS 8 Step by Step

LAMP is the acronyms of Linux, Apache, MySQL and PHP. Apache is the web server to serve files over HTTP protocol. MySQL is the popular database server. PHP is the programming language used for developing web applications. Using these applications, we can create a full fledged web server. The most common way to run PHP applications with Apache is the use of mod_php module. Also the good alternative is to use PHP-FPM, which has several advantages over this. The default installation on CentOS 8 uses PHP-FPM to process php files.

In this tutorial, we will learn how to install and configure LAMP (Linux, Apache, MySQL, and PHP) on CentOS 8. Follow the following steps to install and configure LAMP (Linux, Apache, MySQL, and PHP) on CentOS 8:

1 :  Install Apache

The Apache web server packages are available under the default AppStream repository on CentOS 8. You just need to update the DNF cache and install packages using the following commands.

sudo dnf update 
sudo dnf install httpd httpd-tools

The mod_ssl package provides the functionality to use an SSL certificate for secure HTTP. After installation, enable the httpd service and start.

sudo systemctl enable httpd.service
sudo systemctl start httpd.service

Now check the Apache service status:

sudo systemctl status httpd.service


● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
  Drop-In: /usr/lib/systemd/system/httpd.service.d
   Active: active (running) since Sat 2022-03-22 04:27:24 EDT; 5s ago
     Docs: man:httpd.service(8)
 Main PID: 8644 (httpd)
   Status: "Started, listening on: port 80"
    Tasks: 213 (limit: 8918)
   Memory: 21.5M
   CGroup: /system.slice/httpd.service
           ├─8644 /usr/sbin/httpd -DFOREGROUND
           ├─8650 /usr/sbin/httpd -DFOREGROUND
           ├─8651 /usr/sbin/httpd -DFOREGROUND
           ├─8652 /usr/sbin/httpd -DFOREGROUND
           └─8653 /usr/sbin/httpd -DFOREGROUND

Mar 22 04:27:23 codequs systemd[1]: Starting The Apache HTTP Server...
Mar 22 04:27:24 codequs systemd[1]: Started The Apache HTTP Server.
Mar 22 04:27:24 codequs httpd[8644]: Server configured, listening on: port 80

2 : Install MySQL Server

The latest MySQL 8 packages are available under the AppStrem repository under CentOS 8. Use the following command to install MySQL server including required packages on your system.

sudo dnf -y install @mysql

After completing the installation, enable the MySQL service to auto-start on the system start. Also start service manually for the first time.

sudo systemctl enable mysqld.service
sudo systemctl start mysqld.service

Then check the service current status using the following command:

sudo systemctl status mysqld.service


● mysqld.service - MySQL 8.0 database server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: active (running) since Sat 2022-03-22 02:49:33 EDT; 5min ago
  Process: 5841 ExecStartPost=/usr/libexec/mysql-check-upgrade (code=exited, status=0/SUCCESS)
  Process: 5706 ExecStartPre=/usr/libexec/mysql-prepare-db-dir mysqld.service (code=exited, status=0/SUCCESS)
  Process: 5682 ExecStartPre=/usr/libexec/mysql-check-socket (code=exited, status=0/SUCCESS)
 Main PID: 5798 (mysqld)
   Status: "Server is operational"
    Tasks: 38 (limit: 8918)
   Memory: 442.1M
   CGroup: /system.slice/mysqld.service
           └─5798 /usr/libexec/mysqld --basedir=/usr

Mar 22 02:48:42 codequs systemd[1]: Starting MySQL 8.0 database server...
Mar 22 02:48:45 codequs mysql-prepare-db-dir[5706]: Initializing MySQL database
Mar 22 02:49:33 codequs systemd[1]: Started MySQL 8.0 database server.

The MySQL installation has been completed. Now you can connect the MySQL server without any password but we recommend securing the MySQL installation. The MySQL packages provide mysql_secure_installation command to apply the security. Just run the below command on terminal:

sudo mysql_secure_installation

and follow the on-screen instructions. Below are the details which require user input.

Press y|Y for Yes, any other key for No: y

  • Please enter 0 = LOW, 1 = MEDIUM and 2 = STRONG: 2
  • Re-enter new password: RE ENTER PASSWORD HERE
  • Do you wish to continue with the password provided?(Press y|Y for Yes, any other key for No) : y
  • Remove anonymous users? (Press y|Y for Yes, any other key for No) : y
  • Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y
  • Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y
  • Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y

3 : Install PHP

The Remi repository contains the latest PHP packages for the CentOS 8 Linux system. So first of all, you need to add the REMI repository to your system. Just execute the following command to add the repository.

sudo dnf install dnf-utils http://rpms.remirepo.net/enterprise/remi-release-8.rpm

Then enable the required DNF module for PHP installation. Here we are enabling the module for installing PHP 7.4. You can change this to PHP 7.3 or PHP 7.2 as per your requirements.

sudo dnf module reset php
sudo dnf module enable php:remi-7.4

Once the repository is enabled on your system. Install PHP packages along with required PHP modules.

sudo dnf install php php-mysqlnd

You many also need to install other required php modules as per your application requirements. The below command will install few frequently used php modules:

dnf install php-gd php-zip php-mcrypt php-json php-xml php-gettext php-curl php-intl 

4 : Create Apache VirtualHost

All the packages required for LAMP environment is installed. Now, create the Apache virtual host. By default the Apache uses php-fpm for processing PHP files on CentOS 8 system.

Create and edit virtual host configuration file in the favorite text editor:

sudo vim /etc/httpd/conf.d/codequs.example.com.conf

Add the following content in the configuration file. Make sure to change required parameters.

<VirtualHost *:80>
    ServerAdmin admin@example.com
    DocumentRoot /var/www/html
    ServerName codequs.example.com
    ServerAlias www.codequs.example.com
    ErrorLog logs/codequs.com-error.log
    CustomLog logs/codequs.com-access.log combined

Save the virtual host configuration file and reload Apache to apply changes.

sudo systemctl restart httpd.service

5 : Allow Ports in Firewalld

The CentOS 8 Linux server is ready to serve the application over LAMP environment. If your system has firewalld installed ans active, you need to allow Apache ports. This will allow network users to access web application from remote systems.

The following commands will open the required ports for you.

sudo firewall-cmd --zone=public --permanent --add-service=http
sudo firewall-cmd --zone=public --permanent --add-service=https
sudo firewall-cmd --reload

6 :Test Setup

All done. To test the environment, create a PHP script with phpinfo() function. Place this file to your server document root. Use the below command to do this.

echo "<?php phpinfo(); ?>" > /var/www/html/info.php

Then access info.php using server IP address (for default VirtualHost) for your configured domain in Apache VirtualHost.


Thanks for reading!!!

#php #lamp #centos 

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Install LAMP Stack on CentOS 8 Step by Step
John  Smith

John Smith


Find the Best Restaurant Mobile App Development Company in Abu Dhbai

The era of mobile app development has completely changed the scenario for businesses in regions like Abu Dhabi. Restaurants and food delivery businesses are experiencing huge benefits via smart business applications. The invention and development of the food ordering app have helped all-scale businesses reach new customers and boost sales and profit. 

As a result, many business owners are searching for the best restaurant mobile app development company in Abu Dhabi. If you are also searching for the same, this article is helpful for you. It will let you know the step-by-step process to hire the right team of restaurant mobile app developers. 

Step-by-Step Process to Find the Best Restaurant App Development Company

Searching for the top mobile app development company in Abu Dhabi? Don't know the best way to search for professionals? Don't panic! Here is the step-by-step process to hire the best professionals. 

#Step 1 – Know the Company's Culture

Knowing the organization's culture is very crucial before finalizing a food ordering app development company in Abu Dhabi. An organization's personality is shaped by its common beliefs, goals, practices, or company culture. So, digging into the company culture reveals the core beliefs of the organization, its objectives, and its development team. 

Now, you might be wondering, how will you identify the company's culture? Well, you can take reference from the following sources – 

  • Social media posts 
  • App development process
  • About us Page
  • Client testimonials

#Step 2 - Refer to Clients' Reviews

Another best way to choose the On-demand app development firm for your restaurant business is to refer to the clients' reviews. Reviews are frequently available on the organization's website with a tag of "Reviews" or "Testimonials." It's important to read the reviews as they will help you determine how happy customers are with the company's app development process. 

You can also assess a company's abilities through reviews and customer testimonials. They can let you know if the mobile app developers create a valuable app or not. 

#Step 3 – Analyze the App Development Process

Regardless of the company's size or scope, adhering to the restaurant delivery app development process will ensure the success of your business application. Knowing the processes an app developer follows in designing and producing a top-notch app will help you know the working process. Organizations follow different app development approaches, so getting well-versed in the process is essential before finalizing any mobile app development company. 

#Step 4 – Consider Previous Experience

Besides considering other factors, considering the previous experience of the developers is a must. You can obtain a broad sense of the developer's capacity to assist you in creating a unique mobile application for a restaurant business.

You can also find out if the developers' have contributed to the creation of other successful applications or not. It will help you know the working capacity of a particular developer or organization. Prior experience is essential to evaluating their work. For instance, whether they haven't previously produced an app similar to yours or not. 

#Step 5 – Check for Their Technical Support

As you expect a working and successful restaurant mobile app for your business, checking on this factor is a must. A well-established organization is nothing without a good technical support team. So, ensure whatever restaurant mobile app development company you choose they must be well-equipped with a team of dedicated developers, designers, and testers. 

Strong tech support from your mobile app developers will help you identify new bugs and fix them bugs on time. All this will ensure the application's success. 

#Step 6 – Analyze Design Standards

Besides focusing on an organization's development, testing, and technical support, you should check the design standards. An appealing design is crucial in attracting new users and keeping the existing ones stick to your services. So, spend some time analyzing the design standards of an organization. Now, you might be wondering, how will you do it? Simple! By looking at the organization's portfolio. 

Whether hiring an iPhone app development company or any other, these steps apply to all. So, don't miss these steps. 

#Step 7 – Know Their Location

Finally, the last yet very crucial factor that will not only help you finalize the right person for your restaurant mobile app development but will also decide the mobile app development cost. So, you have to choose the location of the developers wisely, as it is a crucial factor in defining the cost. 

Summing Up!!!

Restaurant mobile applications have taken the food industry to heights none have ever considered. As a result, the demand for restaurant mobile app development companies has risen greatly, which is why businesses find it difficult to finalize the right person. But, we hope that after referring to this article, it will now be easier to hire dedicated developers under the desired budget. So, begin the hiring process now and get a well-craft food ordering app in hand. 

Chet  Lubowitz

Chet Lubowitz


How to install PgAdmin 4 on CentOS 8

pgAdmin is the leading graphical Open Source management, development and administration tool for PostgreSQLpgAdmin4 is a rewrite of the popular pgAdmin3 management tool for the PostgreSQL database.

In this tutorial, we are going to show you how to install pgAdmin4 in Server Mode as a web application using httpd and Wsgi module on CentOS 8.

Install pgAdmin4 on CentOS 8

**01-**To install pgAdmin4 on CentOS 8 we need to add an external repository, so execute the following command:

$ sudo rpm -i https://ftp.postgresql.org/pub/pgadmin/pgadmin4/yum/pgadmin4-redhat-repo-1-1.noarch.rpm

02- After we add the pgAdmin4 repository, let’s use the below command to install pgAdmin4 as server mode:

$ sudo dnf install pgadmin4-web

03- Before proceeding with the configuration of pgAdmin4, we need to install policycoreutils tool:

$ dnf install policycoreutils-python-utils  

04- Once we done installing pgAdmin4, we need to configure the pgAdmin4 by setting up the initial pgAdmin user account

#databases #linux #ubuntu #install pgadmin4 #install pgadmin4 centos #pgadmin #pgadmin 4 install #pgadmin 4 install centos #pgadmin4 #pgadmin4 install centos

Dylan  Iqbal

Dylan Iqbal


Matplotlib Cheat Sheet: Plotting in Python

This Matplotlib cheat sheet introduces you to the basics that you need to plot your data with Python and includes code samples.

Data visualization and storytelling with your data are essential skills that every data scientist needs to communicate insights gained from analyses effectively to any audience out there. 

For most beginners, the first package that they use to get in touch with data visualization and storytelling is, naturally, Matplotlib: it is a Python 2D plotting library that enables users to make publication-quality figures. But, what might be even more convincing is the fact that other packages, such as Pandas, intend to build more plotting integration with Matplotlib as time goes on.

However, what might slow down beginners is the fact that this package is pretty extensive. There is so much that you can do with it and it might be hard to still keep a structure when you're learning how to work with Matplotlib.   

DataCamp has created a Matplotlib cheat sheet for those who might already know how to use the package to their advantage to make beautiful plots in Python, but that still want to keep a one-page reference handy. Of course, for those who don't know how to work with Matplotlib, this might be the extra push be convinced and to finally get started with data visualization in Python. 

You'll see that this cheat sheet presents you with the six basic steps that you can go through to make beautiful plots. 

Check out the infographic by clicking on the button below:

Python Matplotlib cheat sheet

With this handy reference, you'll familiarize yourself in no time with the basics of Matplotlib: you'll learn how you can prepare your data, create a new plot, use some basic plotting routines to your advantage, add customizations to your plots, and save, show and close the plots that you make.

What might have looked difficult before will definitely be more clear once you start using this cheat sheet! Use it in combination with the Matplotlib Gallery, the documentation.


Matplotlib is a Python 2D plotting library which produces publication-quality figures in a variety of hardcopy formats and interactive environments across platforms.

Prepare the Data 

1D Data 

>>> import numpy as np
>>> x = np.linspace(0, 10, 100)
>>> y = np.cos(x)
>>> z = np.sin(x)

2D Data or Images 

>>> data = 2 * np.random.random((10, 10))
>>> data2 = 3 * np.random.random((10, 10))
>>> Y, X = np.mgrid[-3:3:100j, -3:3:100j]
>>> U = 1 X** 2 + Y
>>> V = 1 + X Y**2
>>> from matplotlib.cbook import get_sample_data
>>> img = np.load(get_sample_data('axes_grid/bivariate_normal.npy'))

Create Plot

>>> import matplotlib.pyplot as plt


>>> fig = plt.figure()
>>> fig2 = plt.figure(figsize=plt.figaspect(2.0))


>>> fig.add_axes()
>>> ax1 = fig.add_subplot(221) #row-col-num
>>> ax3 = fig.add_subplot(212)
>>> fig3, axes = plt.subplots(nrows=2,ncols=2)
>>> fig4, axes2 = plt.subplots(ncols=3)

Save Plot 

>>> plt.savefig('foo.png') #Save figures
>>> plt.savefig('foo.png',  transparent=True) #Save transparent figures

Show Plot

>>> plt.show()

Plotting Routines 

1D Data 

>>> fig, ax = plt.subplots()
>>> lines = ax.plot(x,y) #Draw points with lines or markers connecting them
>>> ax.scatter(x,y) #Draw unconnected points, scaled or colored
>>> axes[0,0].bar([1,2,3],[3,4,5]) #Plot vertical rectangles (constant width)
>>> axes[1,0].barh([0.5,1,2.5],[0,1,2]) #Plot horiontal rectangles (constant height)
>>> axes[1,1].axhline(0.45) #Draw a horizontal line across axes
>>> axes[0,1].axvline(0.65) #Draw a vertical line across axes
>>> ax.fill(x,y,color='blue') #Draw filled polygons
>>> ax.fill_between(x,y,color='yellow') #Fill between y values and 0

2D Data 

>>> fig, ax = plt.subplots()
>>> im = ax.imshow(img, #Colormapped or RGB arrays
      cmap= 'gist_earth', 
      interpolation= 'nearest',
>>> axes2[0].pcolor(data2) #Pseudocolor plot of 2D array
>>> axes2[0].pcolormesh(data) #Pseudocolor plot of 2D array
>>> CS = plt.contour(Y,X,U) #Plot contours
>>> axes2[2].contourf(data1) #Plot filled contours
>>> axes2[2]= ax.clabel(CS) #Label a contour plot

Vector Fields 

>>> axes[0,1].arrow(0,0,0.5,0.5) #Add an arrow to the axes
>>> axes[1,1].quiver(y,z) #Plot a 2D field of arrows
>>> axes[0,1].streamplot(X,Y,U,V) #Plot a 2D field of arrows

Data Distributions 

>>> ax1.hist(y) #Plot a histogram
>>> ax3.boxplot(y) #Make a box and whisker plot
>>> ax3.violinplot(z)  #Make a violin plot

Plot Anatomy & Workflow 

Plot Anatomy 




The basic steps to creating plots with matplotlib are:

1 Prepare Data
2 Create Plot
3 Plot
4 Customized Plot
5 Save Plot
6 Show Plot

>>> import matplotlib.pyplot as plt
>>> x = [1,2,3,4]  #Step 1
>>> y = [10,20,25,30] 
>>> fig = plt.figure() #Step 2
>>> ax = fig.add_subplot(111) #Step 3
>>> ax.plot(x, y, color= 'lightblue', linewidth=3)  #Step 3, 4
>>> ax.scatter([2,4,6],
          color= 'darkgreen',
          marker= '^' )
>>> ax.set_xlim(1, 6.5)
>>> plt.savefig('foo.png' ) #Step 5
>>> plt.show() #Step 6

Close and Clear 

>>> plt.cla()  #Clear an axis
>>> plt.clf(). #Clear the entire figure
>>> plt.close(). #Close a window

Plotting Customize Plot 

Colors, Color Bars & Color Maps 

>>> plt.plot(x, x, x, x**2, x, x** 3)
>>> ax.plot(x, y, alpha = 0.4)
>>> ax.plot(x, y, c= 'k')
>>> fig.colorbar(im, orientation= 'horizontal')
>>> im = ax.imshow(img,
            cmap= 'seismic' )


>>> fig, ax = plt.subplots()
>>> ax.scatter(x,y,marker= ".")
>>> ax.plot(x,y,marker= "o")


>>> plt.plot(x,y,linewidth=4.0)
>>> plt.plot(x,y,ls= 'solid') 
>>> plt.plot(x,y,ls= '--') 
>>> plt.plot(x,y,'--' ,x**2,y**2,'-.' ) 
>>> plt.setp(lines,color= 'r',linewidth=4.0)

Text & Annotations 

>>> ax.text(1,
           'Example Graph', 
            style= 'italic' )
>>> ax.annotate("Sine", 
xy=(8, 0),
xycoords= 'data', 
xytext=(10.5, 0),
textcoords= 'data', 
arrowprops=dict(arrowstyle= "->", 


>>> plt.title(r '$sigma_i=15$', fontsize=20)

Limits, Legends and Layouts 

Limits & Autoscaling 

>>> ax.margins(x=0.0,y=0.1) #Add padding to a plot
>>> ax.axis('equal')  #Set the aspect ratio of the plot to 1
>>> ax.set(xlim=[0,10.5],ylim=[-1.5,1.5])  #Set limits for x-and y-axis
>>> ax.set_xlim(0,10.5) #Set limits for x-axis


>>> ax.set(title= 'An Example Axes',  #Set a title and x-and y-axis labels
            ylabel= 'Y-Axis', 
            xlabel= 'X-Axis')
>>> ax.legend(loc= 'best')  #No overlapping plot elements


>>> ax.xaxis.set(ticks=range(1,5),  #Manually set x-ticks
             ticklabels=[3,100, 12,"foo" ])
>>> ax.tick_params(axis= 'y', #Make y-ticks longer and go in and out
             direction= 'inout', 

Subplot Spacing 

>>> fig3.subplots_adjust(wspace=0.5,   #Adjust the spacing between subplots
>>> fig.tight_layout() #Fit subplot(s) in to the figure area

Axis Spines 

>>> ax1.spines[ 'top'].set_visible(False) #Make the top axis line for a plot invisible
>>> ax1.spines['bottom' ].set_position(( 'outward',10))  #Move the bottom axis line outward

Have this Cheat Sheet at your fingertips

Original article source at https://www.datacamp.com

#matplotlib #cheatsheet #python

Hal  Sauer

Hal Sauer


How to Install LAMP Stack on CentOS 8/RHEL 8

A software stack is a set of software tools bundled together. LAMP stands for Linux, Apache, MariaDB/MySQL and PHP, all of which are open source. It is the most common software stack that powers dynamic websites and web applications. Linux is the operating system; Apache is the web server; MariaDB/MySQL is the database server and PHP is the server-side scripting language responsible for generating dynamic web pages.

#centos #redhat #centos server #lamp stack #linux #red hat #red hat server

Hertha  Mayer

Hertha Mayer


Authentication In MEAN Stack - A Quick Guide

I consider myself an active StackOverflow user, despite my activity tends to vary depending on my daily workload. I enjoy answering questions with angular tag and I always try to create some working example to prove correctness of my answers.

To create angular demo I usually use either plunker or stackblitz or even jsfiddle. I like all of them but when I run into some errors I want to have a little bit more usable tool to undestand what’s going on.

Many people who ask questions on stackoverflow don’t want to isolate the problem and prepare minimal reproduction so they usually post all code to their questions on SO. They also tend to be not accurate and make a lot of mistakes in template syntax. To not waste a lot of time investigating where the error comes from I tried to create a tool that will help me to quickly find what causes the problem.

Angular demo runner
Online angular editor for building demo.

Let me show what I mean…

Template parser errors#

There are template parser errors that can be easy catched by stackblitz

It gives me some information but I want the error to be highlighted

#mean stack #angular 6 passport authentication #authentication in mean stack #full stack authentication #mean stack example application #mean stack login and registration angular 8 #mean stack login and registration angular 9 #mean stack tutorial #mean stack tutorial 2019 #passport.js