Today I was doing some updates on the server and realized that not much is said about this topic, so I decided to talk about how to install PHP modules on Linux.

Before talking about heredoc or nowdoc, we need to know that they are different ways to specify a string in PHP. Maybe I should have talked about this topic in the section about variables, but it would be too long for someone to read quickly. I came up with this post while creating an article about the DOMDocument class in PHP, which is quite long. However, it is designed to help you find what you need to know quickly. I don't expect anyone to read the entire post.

We will see the different extensions provided by PHP and a library used by PHP programmers to connect to our MySQL databse

Both include and require statements are used to include the entire text from one file into another, but they have a difference in behavior. The include statement will produce a warning if the file is not found, while the require statement will produce a fatal error.

Check if a variable is defined and not null, so, if the variable is not defined it will return false, if the variable is null it will return false. If the variable is defined, it will return true.