Steps to Run the GUI Based Debugger:

1. Save your Perl program in a file, say hello.pl. To start the debugger, type the following command if you are using the bash:

   % PERL5LIB=~cs898n/pub/ptkdb; export PERL5LIB
   % perl -I`echo ~cs898n/pub/ptkdb` -d:ptkdb hello.pl
   

   If you are using the csh, you can set the environment variable as follows:

   % setenv PERL5LIB cs898n/pub/ptkdb
   

   Note: You only need to set the environment variable once. If you are using the bash, you can do it by inserting the following line to the bash startup file ~/.bash_profile:

   PERL5LIB=~cs898n/pub/ptkdb; export PERL5LIB
   

2. The graphical user interface of the debugger is self-explanatory. You can get more details from the Ptkdb User Guide.
   
   
3. If you don't like this graphical debugger, you can use the manual source debugger by typing the following command:

   % perl -d hello.pl
   

   You can read the online man pages for the Perl source debugger with the man command:

   % man perldebug
   

   If you are using the xemacs, you can invoke the Perl source debugger in the Emacs.