To get most out of your MySQL database, it is important to understand how to connect from your custom PHP program to MySQL database.

This tutorial explains the following three methods along with appropriate example PHP program, which will explain how to connect from your PHP to MySQL database.

• Connect using mysqli extension (Recommended)
• Connect using PDO (Recommended)
• Connect using traditional legacy mysql_ functions (Deprecated)

For this, you should install php-mysql package.
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If you are running Nginx webserver, it is important for you to understand how the location directive works.

Nginx uses location directive to decide what configuration it should apply based on prefix or the pattern in the incoming URL.

For example, from what directory it should serve the image files when an URL ends with *.gif or *.png or any other image filename extension.

In this tutorial, we’ll explain the following with proper examples:

1. Default Location Directive Setup
2. Change the Default Nginx Root Location (i.e DocumentRoot)
3. Define Custom 404 Page Not Found Using Location
4. Define Multiple Custom 50x Server Errors using Location
5. Serve Your Website Images from a Custom Location
6. Exact Match Using = (Equalto Sign) Location Modifier
7. Case-Sensitive Regular Expression Match Using ~ (Tilde Sign)
8. Case-InSensitive Regular Expression Match Using ~* (Tilde-Asterisk Sign)
9. ^~ Best Non RegEx Match (Carat-Tilde Sign)
10. Nginx Location Related Error Messages
11. Summary of Location Modifiers
12. Define Custom Named Location Using @ (At Sign)
13. Nginx Location Matching Processing Sequence and Logic

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Jenkins is an open source DevOps tool that will help you to deploy and automate your enterprise application.

In Jenkins, by default you can create users, but not groups.

So, if you want groups in Jenkins, you have the following few options:

• Use OpenLDAP with Jenkins
• Use Active Directory with Jenkins
• Use Unix user/group database. This will use PAM library to integrate with Jenkins.
• Use “Role-based authorization strategy” plugin for Jenkins

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PostgreSQL is an enterprise level open source database.

This is one of the most reliable, robust, feature-rich, and powerful relational database system.

Most importantly, PostgreSQL is well known for its ability to handle heavy load, and deliver high performance. This supports pretty much all the features that you would ever need from a RDBMS system.

If you are new to PostgreSQL, this tutorial will give you an excellent jump-start.
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In AWS, when you launch any EC2 Linux instance, you should select a key pair for that particular instance.

AWS key pair will be in the standard private key format with .pem file extension

But if you are using PuTTY on your Windows laptop to login to AWS instance, you have a problem.

PuTTY doesn’t support PEM format. PuTTY understands only it’s own PPK format.

PPK stands for Putty Private Key.
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Mirth Connect is an Open Source Integration Engine that is primarily used in the Health Care domain.

This support various health care standards (HL7, XML, EDI/X12, DICOM etc) that will help enterprise to integrate different systems, and let them talk to each other in a common language.

MirthConnect interface engine also supports various standard protocols (for example, TCP, HTTP, JDBS, SFTP, etc.) to connect two systems.

By default, when you install mirthconnect it uses Apache Derby as storage engine. But, it supports pretty much all popular databases including MySQL / MariaDB, PostgreSQL, Oracle and SQL Server.

In this tutorial, we’ll explain how to install MirthConnect open source software, and configure it to talk to MySQL database on Linux platform.
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If you are a Linux sysadmin or a developer, you probably already know how to create and sign a SSL certificate for your webserver.

But, if your corporate environment also has some Windows servers and applications, you may end-up in a situation, where you may have to digitally sign Windows files.

The process of digitally signing a Windows files such as EXE, or DLL, or OCX, or CAB files is know as Code Signing.

For this, you should purchase a Code Sign certificate from a trusted provider like Symantec, or Thawte, or Godaddy, etc.

Once you purchase your code sign certificate, then you should sign your file using a tool called signtool.
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