While PHP-developing it sometimes is just too tedious to do those 'add a echo here and there, then reload and search the echoed strings on the screen'-loops. So I searched for a debugger for my favourite editor emacs. After a lengthy install procedure I finally got it running: With geben on emacs you can debug PHP (step through and evaluate expressions).

The post steps you through the installation - adding in xdebug, changing the PHP configuration, and getting and installing geben (along with other required packages).