GNU DDD is a graphical front-end for command-line debuggers such as GDB, DBX, WDB, Ladebug, JDB, XDB, the Perl debugger, the bash debugger bashdb, the GNU Make debugger remake or the Python debugger pydb. Besides usual front-end features such as viewing source texts. DDD has become famous through its interactive graphical data display, where data structures are displayed as graphs. You can support the principle of software freedom by buying stuff from the FSF shop. To run DDD, you need the GNU debugger (GDB), version 4.16 or later (or depending on the program to be debugged, possibly other command-line debuggers such as Ladebug, JDB, XDB, the Perl debugger, the bash debugger bashdb, the GNU Make debugger remake, or the Python debugger pydb).