AWK is a programming language designed for text processing and is typically used as a data extraction and reporting tool. It is a standard feature of most Unix-like operating systems. The AWK language is a data-driven scripting language consisting of a set of actions to be taken against streams of textual data (either run directly on files or used as part of a pipeline) for purposes of extracting or transforming text, such as producing formatted reports. The language extensively uses the string data type, associative arrays (that is, arrays indexed by key strings) and regular expressions. AWK was created at Bell Labs in the 1970s, and its name is derived from the surnames of its authors: Alfred Aho, Peter Weinberger and Brian Kernighan. The acronym is pronounced the same way as the name of the bird auk, which acts as an emblem of the language such as on "The AWK Programming Language" book cover (the book is often referred to by the abbreviation "TAPL"). When written in all lowercase letters as awk, it refers to the Unix or Plan 9 program that runs scripts written in the AWK programming language.