LEMP is a group of open source software stack used to setup web server, database and PHP on a Linux operating system to serve dynamic web pages. LEMP stands for Linux, Nginx (pronounced as Engine X) web server, MySQL database and PHP. Another stack called LAMP (alternative to LEMP) is…

Recently one of my client provided a fresh VPS and asked me to install PHP 7, Apache and MySQL. While installing PHP, I encountered the below error: root@webimage:~# apt-get install php Reading package lists… Done Building dependency tree Reading state information… Done E: Unable to locate package php Solution: By…

COMODO SSL Certificate Installation – I installed LEMP stack for one of my client on his CentOS 7 machine and configured SSL certificate obtained from COMODO for his domain. It was working fine in desktops and mobile devices. But my client came back with an issue and said that he…

While working on a migration of a Joomla powered website on to a new VPS with PHP version 7.0 and Apache 2.4, encountered the an error “Call to undefined function simplexml_load_file()“. Below is the complete error. Error displaying the error page: Call to undefined function simplexml_load_file(): Call to undefined function simplexml_load_file()…

If you are getting an error “GPG error and Duplicate sources.list” while configuring MySQL repository for installing MySQL server version 5.7, then here’s how you can udpate GPG key. #apt-get update ….. W: GPG error: http://repo.mysql.com jessie InRelease: The following signatures were invalid: KEYEXPIRED 1487236823 KEYEXPIRED 1487236823 KEYEXPIRED 1487236823 W: Duplicate…

I have been migrating one of the Joomla website and was stuck with a “PHP fatal error Uncaught Error: Call to undefined function apc_fetch()”. If you are stuck with a similar error, then here’s how you can solve it. Before that, below is the snapshot of the error: Fatal error: Uncaught…

This tutorial will explain how to install MySQL v5.7 on Debian 8 Jessie server. The default repositories in Debian 8 will install MySQL version up to 5.6, so if you ever want to install 5.7, then you need to setup a repository that has 5.7 RPMs. Alternatively, you can source compile…

In continuation to my tutorial on Installation of Datawrapper and possible errors with solutions, here’s another error in Apache – “Symbolic link not allowed or link target not accessible“. Below is the complete error message from Apache error_log. AH00037: Symbolic link not allowed or link target not accessible: /public_html/datawrapper/www/static/plugins/visualization-raphael-chart, referer: http://domain.com/chart/AJmIh/preview?innersvg=1&random=49981 I…

Here’s another error related to Datawrapper installation – “PHP warning:  It is not safe to rely on system’s timezone settings“. Below is the complete error message from Apache error_log file. [Thu Feb 23 13:18:15.040832 2017] [:error] PHP Warning:  phpinfo(): It is not safe to rely on the system’s timezone settings. You…

I recently wrote a tutorial on Installation of DataWrapper and its possible errors with solutions. Here, I’m writing about another error with a solution for the benefit of the Datawrapper community. These errors are mostly non Datawrapper based i.e, it is all related to either Apache configuration or PHP server configurations. Here’s…

Question: I would like to replace a text with a link in anchor tag of a html file. The challenge is that, the project contains hundreds of such HTML files and replacing a text in all those files manually is not smart way of doing it. So the question is, how…

This tutorial explains how to adjust open_basedir attribute in PHP configuration and in case of shared hosting, learn to disable open_basedir via cPanel. Question: Recently I worked for a client to install Datawrapper application on his Debian Jessie shared hosting server. I did follow all the steps given in the installation…

Question:  I have installed Nginx on a Ubuntu Xenial machine through apt-get.  However the service failed to start with an error message as “Address family not supported by protocol“. Below is the complete nginx error message: — Unit nginx.service has begun starting up. Feb 19 23:46:27 nginx[5069]: nginx: [emerg] socket()…

This tutorial will explain how to install PHP and its dependent packages on GNU Linux. If the Linux is installed with minimal packages,  then you need to install packages such as add-apt-repository, apt-transport-https, ca-certificates etc., as these packages will be used to download the other packages during apt-get install. Step 1:…

It’s quite common for an administrator to edit sudoers file and allow users to execute administrative commands. But what if you make an error? The sudo command is going to fail isn’t? That’s what exactly I did while installing OpenStack on a Ubuntu machine. Well, here’s what I saw after…

You would have read our earlier posts on Openstack installation and its various configuration setup’s and solutions to installation errors. Here’s another one on this topic. On excitement, I created an Instance with a flavor of m1.small and started installing many packages.  Later I realized that the flavor I have…

I recently wanted to create a mailing list in Thunderbird and send out a confirmation email for 40 odd participants registered for an event. I know it’s not going to be easy to add all email addresses in the To: field, so I found out a better way of doing it and…

Question: I recently burnt a DVD and was trying to mount it on my Ubuntu box. It worked, when I tried to mount it manually, but failed to mount via /etc/fstab for automount. The error message indicated that the file system type is wrong. But I did not know how to…

When I was stumbling upon to implement Single Sign-On in one of my web-project, came across a solution implemented by StackOverflow using HTML5 LocalStorage. While following it up with the technical details, came across a troubleshooting page for auto-login. The page would run few tests to check for the availability of…