Xdebug on Linux

To debug PHP applications with PHP Tools for Visual Studio Code, it is necessary to install and enable Xdebug extension in PHP.

Step-by-step guide

  1. Install Xdebug

  2. Verify the installation

    php -v

    You should see output like this:

    PHP 8.1.7 (cli) (built: Jun  7 2022 18:21:38) (NTS gcc x86_64)
    Copyright (c) The PHP Group
    Zend Engine v4.1.7, Copyright (c) Zend Technologies
        with Zend OPcache v8.1.7, Copyright (c), by Zend Technologies
        with Xdebug v3.1.5, Copyright (c) 2002-2022, by Derick Rethans

    If the output contains Xdebug, you are done. If not, continue with the guide.

  3. Locate php.ini by running the following command:

    php --ini

    The output should look similar to this:

    Configuration File (php.ini) Path: /etc/php/8.1/cli
    Loaded Configuration File:         /etc/php/8.1/cli/php.ini
    Scan for additional .ini files in: /etc/php/8.1/cli/conf.d
    Additional .ini files parsed:      /etc/php/8.1/cli/conf.d/10-opcache.ini,

    If there is an ini file with xdebug in the name, open that one. Otherwise, create a new file in conf.d folder. You can name it 99-xdebug.ini and copy the following content to the file:


    Note Make sure Xdebug configuration is present in the php --ini output after the opcache.ini configuration.

  4. (Optional) You can turn xdebug.start_with_request=yes (in Xdebug 2 it was xdebug.remote_autostart = 1). This option will activate the debugger on each request. By default, Xdebug initiates the debug session only when it's instructed to, e.g. when the URL has XDEBUG_SESSION_START query parameter. That might complicate scenarios like debugging AJAX requests.

  5. Restart the webserver to reload the settings, if applicable.

Things to try:

You should have Xdebug configured by now, you can try a simple scenario:

  1. Open Visual Studio Code

  2. Open a simple PHP file, like:

    echo "hello world";
  3. Add a breakpoint by pressing F9 to a statement (echo in the example)

  4. Start a debug session by pressing F5 and selecting Debug Current script in Console

  5. The breakpoint gets hit

See Also