More than a command line, less than a GUI, the free and insanely powerful GNU text editor includes quasi-graphical support for a simple but intuitive interface to the perl debugger via the cperlmode (see Chapter 3). To start a debug session in the active buffer, enter M-x perldbRET, and you’ll get something like Figure 7-3, where one subwindow contains the source code, and the other is for interactions with the debugger. Figure 7-3. The emacs interface to the Perl debugger via cperl-mode The syntax highlighting is evident in the source code when viewed in color. (Keywords in blue, subroutine prototypes in heavy blue, comments in red, and double-quoted strings in gray; if you don’t like any of those assignments, they are easy to change.) Emacs is available with any Linux system and can be downloaded for virtually any platform from http://www.gnu.org/software/emacs/emacs.html. Don’t overlook the use of debuggers as a teaching tool. I often use ptkdb to monitor the evolution of a variable (scalar, array, hash) as a program executes. Such a demonstration allows a new programer to observe a variable’s value and scope in various situations which is quite useful when you are forced to explain the difference between lexical variables and package variables.
Note: If you are looking for high quality webhost to host and run your jsp application check Vision jsp hosting services