Mastering Perl helps readers to learn the Perl programming language with real-world examples. High-level, interpreted, and multipurpose, Perl’s roots are in text manipulation. It is used for UI development in system administration, networking, and other fields, borrowing heavily from C and Shell scripts. Among programmers, Perl is also known as "Pathologically Eclectic Rubbish Lister" or "Practically Everything Really Likable." Since Perl’s inception, it has mostly been used for text processing, namely the extraction of data from text files and its subsequent transformation into other formats. In addition to being interoperable with HTML, XML, and other markup languages, Perl provides cross-platform compatibility. It is Open Source, meaning it is free to use and licensed under both the Artistic and GNU General Public Licenses (GPL).