First PHP Program: Run, Read, and Debug the Output

First Program Goal

Your first program should prove three things: PHP can execute the file, you can identify the generated output, and you know where to look when the result is wrong.

This lesson uses one small status page so syntax, HTML output, and the request path stay visible.

Create the File

Create hello.php inside the web root. In XAMPP that is commonly C:\xampp\htdocs. Start Apache and open the file through a URL such as http://localhost/hello.php.

The .php extension matters because the web server uses its PHP configuration to decide which files should be executed.

Hello PHP

A PHP statement normally ends with a semicolon. echo is a language construct that writes one or more values to the response.

A Small Status Page

<?php
$course = 'PHP';
$lesson = 1;

echo "<h1>{$course} Course</h1>" . PHP_EOL;
echo "<p>Lesson {$lesson} is running.</p>";

Output

<h1>PHP Course</h1>
<p>Lesson 1 is running.</p>

Double-quoted strings interpolate the two variables before echo writes the HTML response.

Echo and Print

Use echo for ordinary output. print also writes one value and returns 1, but that return value is rarely useful in beginner application code.

Neither construct automatically escapes HTML. Later form lessons use htmlspecialchars() before inserting untrusted text into a page.

Construct	Values per statement	Return value	Typical choice
echo	One or more	None	Normal response output
print	One	1	Legacy or expression-specific code

Run from the CLI

The same file can run without Apache when it does not depend on an HTTP request. From its directory, execute php hello.php. HTML tags will appear as text because a terminal does not render HTML.

Terminal-Friendly Output

<?php
$topic = 'PHP syntax';
echo "Now learning: {$topic}" . PHP_EOL;

Output

Now learning: PHP syntax

First Run Failures

Symptom	Likely cause	Fix
Browser shows <?php	File was served without PHP execution	Use Apache/PHP and a localhost URL
404 Not Found	URL does not match the web-root path	Check the file name and directory
Parse error	PHP syntax is incomplete	Read the reported file and line, then inspect nearby punctuation
Blank page	No output or errors are hidden	Run php -l hello.php and inspect the error log

Read the First Run

0 of 2 checked

Q1. Why should hello.php be opened through localhost?

To execute it through the server PHP runtime To convert PHP into JavaScript To install a database

Q2. What does php -l hello.php check?

Database access Syntax Browser CSS

First Program Failure Boundary

Source code served as text
If the browser displays PHP source, the request did not pass through a configured PHP handler. Stop and fix the web-server mapping before exposing files containing secrets.

Try this next

Change the Response

0 of 2 completed

Add a second value
Add a $completed variable and print it in a second paragraph. Predict the exact HTML before refreshing.
Trigger and repair a parse error
Remove one semicolon, run php -l, record the message, then restore the statement. The reported line can be after the actual missing punctuation.

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