Commonly used paths -

Perl: /usr/bin/perl
Perl 5: /usr/bin/perl5.00503
Sendmail: /usr/sbin/sendmail
Date: /bin/date
PHP: /usr/bin/php
mySQL: /usr/bin/mysql
ImageMagick: /usr/bin/convert OR /usr/local/bin/convert

Document Root: /home/username/
WWW Directory: /home/username/public_html/
CGI Directory: /home/username/public_html/cgi-bin/