Perl, which stands for Practical Extraction and Report Language, is an interpreted high-level programming language developed by Larry Wall. Its an Open Source software, licensed under the GNU General Public License (GPL) with the best features from other languages such as C, awk, sed, sh and BASIC Perl supports unicode.
CGI (common Gateway Interface) allows to use a program behind the scenes to perform tasks that cannot be done through HTML. For this feature, Perl is one of the most preferred languages. For all this flexibility and ease of use, CGI Perl programming is used along with HTML, PHP and CSS very commonly.