1# PCRE2 - Perl-Compatible Regular Expressions 2 3The PCRE2 library is a set of C functions that implement regular expression 4pattern matching using the same syntax and semantics as Perl 5. PCRE2 has its 5own native API, as well as a set of wrapper functions that correspond to the 6POSIX regular expression API. The PCRE2 library is free, even for building 7proprietary software. It comes in three forms, for processing 8-bit, 16-bit, 8or 32-bit code units, in either literal or UTF encoding. 9 10PCRE2 was first released in 2015 to replace the API in the original PCRE 11library, which is now obsolete and no longer maintained. As well as a more 12flexible API, the code of PCRE2 has been much improved since the fork. 13 14## Download 15 16As well as downloading from the 17[GitHub site](https://github.com/PCRE2Project/pcre2), you can download PCRE2 18or the older, unmaintained PCRE1 library from an 19[*unofficial* mirror](https://sourceforge.net/projects/pcre/files/) at SourceForge. 20 21You can check out the PCRE2 source code via Git or Subversion: 22 23 git clone https://github.com/PCRE2Project/pcre2.git 24 svn co https://github.com/PCRE2Project/pcre2.git 25 26## Contributed Ports 27 28If you just need the command-line PCRE2 tools on Windows, precompiled binary 29versions are available at this 30[Rexegg page](http://www.rexegg.com/pcregrep-pcretest.html). 31 32A PCRE2 port for z/OS, a mainframe operating system which uses EBCDIC as its 33default character encoding, can be found at 34[http://www.cbttape.org](http://www.cbttape.org/) (File 939). 35 36## Documentation 37 38You can read the PCRE2 documentation 39[here](https://PCRE2Project.github.io/pcre2/doc/html/index.html). 40 41Comparisons to Perl's regular expression semantics can be found in the 42community authored Wikipedia entry for PCRE. 43 44There is a curated summary of changes for each PCRE release, copies of 45documentation from older releases, and other useful information from the third 46party authored 47[RexEgg PCRE Documentation and Change Log page](http://www.rexegg.com/pcre-documentation.html). 48 49## Contact 50 51To report a problem with the PCRE2 library, or to make a feature request, please 52use the PCRE2 GitHub issues tracker. There is a mailing list for discussion of 53 PCRE2 issues and development at pcre2-dev@googlegroups.com, which is where any 54announcements will be made. You can browse the 55[list archives](https://groups.google.com/g/pcre2-dev). 56 57