New in Xdebug 2.2: Colours on the command line

This is the first article in a series about new features in Xdebug 2.2. Besides support for PHP 5.4, there are a few that might be of interest.

Xdebug has overloaded var_dump() with xdebug_var_dump() for a long time and the overloaded function could be configured with a few configuration settings. There is xdebug.var_display_max_data to configure how much of a string should be shown; xdebug.var_display_max_children to configure how many children in an array should be shown and xdebug.var_display_max_depth to configure how many levels "deep" the var_dump() should go on for. This functionality was available for when PHP had its html_errors setting on as is usually the case in a web environment1.

Xdebug 2.2 adds this same functionality to the non-HTML environment: the command line. Now the overloaded var_dump() and native xdebug_var_dump() functions also accept the three aforementioned settings:

derick@whisky:~$ php \
        -dxdebug.var_display_max_data=8 \
        -dxdebug.var_display_max_children=4 \
        -r 'var_dump( "a longer string", array( 1, 2, 3, 4, 5, 6, 7 ) );'


string(15) "a longer"...
array(7) {
  [0] =>
  [1] =>
  [2] =>
  [3] =>

  (more elements)...

Now, to be fair. This is all a side effect; and merely an add-on to a patch by Michael Maclean. He wrote a patch that adds colours to the output on the command line by using ANSI escape codes. This patch also made the overloaded var_dump() listen to the limiting settings for variable display. After his patch, the following was the behaviour on the command line as long as stdout is a tty and xdebug.cli_color is set to 1.


I have extended this so that the settings regarding data display also work without xdebug.cli_color set to 1. Further more, in Xdebug 2.2.0RC1, setting xdebug.cli_color to 2 forces the colours from being shown, even if stdout is not a tty.

Initially, the colour coding of errors and var_dump() output, would only work on a Unix system where ANSI escape codes are commonly supported. After the release of Xdebug 2.2.0RC1, Chris Jones submitted a bug report suggesting that this functionality could also be available on the Windows console. I wasn't aware that Windows could do this anymore since they dropped ANSI.SYS but apparently there is a tool, ANSICON, that reimplements this. From the next release, Xdebug 2.2.0RC2, Xdebug will now also check whether the ANSICON environment variable is set, just like Xdebug would check whether stdout is a tty on a Unix platform. As a result, the equivalent console output as shown before looks like the following on Windows (providing ANSICON is installed):


Now the only thing left is adding complete documentation for this feature ;-)

As always, if you think Xdebug is a valuable tool, have a look at


This article has a short URL available:


would you accept a patch to add a parameter to xdebug_var_dump to always emit ANSI codes even in a webserver SAPI? This could be extemely handy for curl-based debugging of APIs.

If so, I would look into making this happen (with the disclaimer that my C is very, very rusty)

@Philip; Sadly, we can't do that as var_dump() and xdebug_var_dump() take one or more variables as arguments to dump.

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    : Except for in PHP 5.3, where this sadly was turned off by default.

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