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PHP basics

This chapter will go through a simple PHP program and show you basic PHP syntax.

Hello world

Let's create a hello world PHP program, and display the output in the command line and in browser.

Create a new file called hello.php with the following contents:

<?php

echo 'Hello world';

And run it in the command line with:

php hello.php

You should see output similar to this:

Hello world

PHP tags

First line in above file is a so called opening PHP tag - <?php. PHP code needs to be wrapped in PHP tags for PHP to be able to parse it. You can also embed the PHP code directly in the HTML file. For example, let's create a file php-and-html.php:

<html>
    <body>
        <?php echo 'Hello world'; ?>
    <body>
</html>
  • Opening PHP tag: <?php
  • Closing PHP tag: ?>

And display it in the browser:

php -S localhost:8000 php-and-html.php

Now, visit URL http://localhost:8000 in your favourite browser, and you should see output of Hello world.

Comments

Comments in code are language elements that indicate which parts of the code should not be parsed and processed. PHP provides two types of comments:

  • Single line comments:
<?php

// This is a single line comment.
echo 'Hello world';

And multiline comments:

<?php

/*
This is multiline comment.
*/
echo 'Hello world';

Expressions

Expressions are basic building block of any language, including PHP.

What's next?

After the introduction chapters, it is time to learn something more about PHP language syntax. Proceed to the next PHP language reference chapter.



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Content of this work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license. Code snippets in examples are published under the CC0 1.0 Universal (CC0 1.0). Thanks to all contributors.