Definition: Compose a new way to ask the same question. The new question must be asking the exact same thing as the original question does. Without any other information, you should be able to tell that the original question and the new question are the same. Preserve bracketed phrases in your new question. You can change the rest of the question provided the above requirements are satisfied. The new question must have a natural, fluent formulation, as if it were composed by a native English speaker. You will be given three pieces of information to help you create better questions. Those are: "Answer": the answer to the question, e.g., "Honolulu". "Answer Type": the type of the answer, e.g., "Location". "Auxiliary Information" is a detailed description of some concepts mentioned in the question, if any.
Input: original question: Which software is written in [Perl]?
answer: pidgin, movable type, amavis...
answer type: Software.
auxiliary information: Perl is a family of high-level, general-purpose, interpreted, dynamic programming languages. The languages in this family include Perl 5 and Perl 6. Though Perl is not officially an acronym, there are various backronyms in use, the most well-known being "Practical Extraction and Reporting Language". Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Perl 6, which began as a redesign of Perl 5 in 2000, eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from one another. The Perl languages borrow features from other programming languages including C, shell scripting, AWK, and sed. They provide powerful text processing facilities without the arbitrary data-length limits of many contemporary Unix commandline tools, facilitating easy manipulation of text files. Perl 5 gained widespread popularity in the late 1990s as a CGI scripting language, in part due to its unsurpassed regular expression and string parsing abilities.

[Perl] is used to write what software?