Free PHP course. Sign Up for tracking progress →

PHP: Hello, World!

As is our tradition, we'll begin by writing the 'Hello, World!' program. The program will print the following text:

Hello, World!

Output to the screen is done with a special command echo, followed by a single or double-quoted string to be output. Be sure to put a semicolon at the end.


echo 'Hello, World!'; // => Hello, World!

There are other ways to display a string on the screen. For example, you can use the function (a concept we will get to know later) print_r(). In this case, the string is entered in parentheses immediately after the function name. You also need to put ; at the end.


print_r('Hello, World!');

In simple situations, there's no difference between these constructions. You can use either one method of output or the other. In more complex cases, where you want to display not just numbers or strings, but, for example, arrays, echo won't be able to do this, but print_r() will display everything.


Copy the exact code from the instructions into the editor and run it by clicking «Run».


print_r('Hello, World!');

Note: If you write heLLo, woRld! instead of Hello, World!, it will be considered different text because upper and lower case letters are different characters. Case is important! This rule affects almost everything in coding, so make sure you get used to paying close attention to the case at all times.

The exercise doesn't pass checking. What to do? 😶

If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:

  • Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨

Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.

My code is different from the teacher's one 🤔

It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.

In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.

I've read the lessons but nothing is clear 🙄

It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.

By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.

If you got stuck and don't know what to do, you can ask a question in our community