Using ptkdb as a GUI

You can use debuggers other than the one supplied with Perl
Pass it as a command-line argument.
For example, use Andrew Page's graphical debugger (requires Tk) Devel::ptkdb.pm
perl -d:ptkdb debug.code
- As with the standard debugger, notations are:
  
  breakable lines (plain type)
  
  current line (blue highlighting)
  
  lines with breakpoints (red highlighting)
- In the expression pane, monitor variables.
- Many of the advanced features of the debugger are available, with the convenience of a graphical interface.