The Perl programming language was invented by Larry Wall; his version 1.000 was presented in 1987. Perl is said not to be an acronym, but still you occasionally see it said to represent ‘Practical Extraction and Report Language’ or ‘Pathologically Eclectic Rubbish Lister’. The word ‘Perl’ (with a capital P) refers to the programming language as such, whereas ‘perl’ refers to the interpreter (implementation). Larry Wall originally invented the language to help out in system administration and in the analysis of huge text files, but through the years Perl has been continuously developed and has for many years been widely used in areas such as web programming and bioinformatics.

The information found in this appendix is very far from a complete description of Perl. The focus here is on the features of Perl that are mentioned in this book. There are certain important elements that are left out, such as variable references and object-oriented approaches. For more extensive information the reader is referred to other sources as listed towards the end of this appendix – for example, Perl Programming, for which Larry Wall is one of the coauthors.