was made available in releases of UNIX System V. To avoid confusion with the incompatible older version, this version was sometimes called "new awk" or nawk. This implementation was released under a free software license in 1996 and is still maintained by Brian Kernighan (see external links below). Old versions of Unix, such as UNIX/32V, included awkcc, which converted AWK to C. Kernighan wrote a program to turn awk into C++; its state is not known. BWK awk, also known as nawk, refers to the version by Brian Kernighan. It has been dubbed the "One True AWK" because of the use of the term in association with the book that originally described the language and the fact that Kernighan was one of the original authors of AWK. FreeBSD refers to this version as one-true-awk. This version also has features not in the book, such as tolower and ENVIRON that are explained above; see the FIXES file in the source archive for details. This version is used by, for example, Android, FreeBSD, NetBSD, OpenBSD, macOS, and illumos. Brian Kernighan and Arnold Robbins are the main contributors to a source repository for nawk: . gawk (GNU awk) is another free-software implementation and the only implementation that makes serious progress implementing internationalization and localization and TCP/IP networking. It was written before the original implementation became freely available. It includes its own debugger, and its profiler enables the user to make measured performance enhancements to a script. It also enables the user to extend functionality with shared libraries. Some Linux distributions include gawk as their default AWK implementation. As of version 5.2 (September 2022) gawk includes a persistent memory feature that can remember script-defined variables and functions from one invocation of a script to the next and pass data between unrelated scripts, as described in the Persistent-Memory gawk User Manual: . gawk-csv. The CSV extension of gawk provides facilities for handling input and output CSV formatted data. mawk is a very fast AWK implementation by Mike Brennan based on a bytecode interpreter. libmawk is a fork of mawk, allowing applications to embed multiple parallel instances of awk interpreters. awka (whose front end is written atop the mawk program) is another translator of AWK scripts into C code. When compiled, statically including the author's libawka.a, the resulting executables are considerably sped up and, according to the author's tests, compare very well with other versions of