# Perl Compatible Regular Expressions

> software library for interpreting regular expressions

**Wikidata**: [Q125267](https://www.wikidata.org/wiki/Q125267)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Perl_Compatible_Regular_Expressions)  
**Source**: https://4ort.xyz/entity/perl-compatible-regular-expressions

Here’s the structured knowledge entry for **Perl Compatible Regular Expressions (PCRE)**:

---

## Summary  
Perl Compatible Regular Expressions (PCRE) is a software library for interpreting regular expressions, designed to closely mimic Perl's regex syntax. It is widely used for pattern matching in text processing across multiple operating systems. PCRE is distributed as free software under the 3-clause BSD License.

## Key Facts  
- **Developer**: Philip Hazel  
- **License**: 3-clause BSD License  
- **Latest Stable Version**: 10.33 (released April 16, 2019)  
- **Operating Systems**: Linux, Unix-like systems, Microsoft Windows  
- **Primary Use**: Pattern matching in text processing  
- **Followed By**: PCRE2 (Perl Compatible Regular Expressions 2)  
- **License**: 3-clause BSD License  
- **Developer**: Philip Hazel  

## Key Facts  
- **Developer**: Philip Hazel  
- **Initial Release**: Earliest documented version is 8.43 (2019-02-23), with PCRE2 versions like 10.32 (2018-09-10) and 10.33 (2019-04-16).  
- **License**: Distributed under the 3-clause BSD License.  
- **Operating Systems**: Compatible with Linux, Unix-like systems, and Microsoft Windows.  
- **Successor**: PCRE2 is the modern iteration, replacing the original PCRE library.  
- **Source Code**: Hosted on GitHub under the PCRE2Project organization.  
- **Documentation**: User manuals available in English via official project pages.  
- **Package Availability**: Included in major Linux distributions (Debian, Fedora, Arch Linux, etc.).  

## FAQs  
### Q: What is PCRE used for?  
A: PCRE is primarily used for pattern matching in text processing, enabling developers to search, replace, and validate strings using Perl-like regular expressions.  

### Q: Is PCRE free software?  
A: Yes, PCRE is free software distributed under the 3-clause BSD License, allowing users to run, modify, and redistribute it freely.  

### Q: What is the difference between PCRE and PCRE2?  
A: PCRE2 is the successor to PCRE, offering improved performance, enhanced features, and better Unicode support while maintaining backward compatibility with the original library.  

## Why It Matters  
PCRE revolutionized text processing by providing a standardized, Perl-compatible regex library that could be integrated into various programming languages and tools. Its widespread adoption in applications like web servers (e.g., Apache, Nginx) and programming languages (e.g., PHP, Python) underscores its importance in modern computing. By offering consistent regex behavior across platforms, PCRE eliminated fragmentation and simplified complex text-matching tasks. Its successor, PCRE2, continues this legacy with optimizations for modern use cases.  

## Notable For  
- **Perl Compatibility**: Closely emulates Perl’s regex syntax, making it a go-to choice for developers familiar with Perl.  
- **Cross-Platform Support**: Runs on Linux, Windows, and Unix-like systems, ensuring broad applicability.  
- **Open Source**: Licensed under the permissive 3-clause BSD License, encouraging widespread use and modification.  
- **Longevity**: Maintained for decades, with active development transitioning to PCRE2.  
- **Integration**: Embedded in major software projects, including programming languages and web servers.  

## Body  
### Development and Versions  
- **Original PCRE**: Early versions like 8.43 (2019) were widely used before PCRE2's release.  
- **PCRE2**: Introduced as a successor, with versions like 10.32 (2018) and 10.33 (2019) offering enhanced features.  

### Technical Features  
- **Pattern Matching**: Supports Perl-like regex syntax for advanced text processing.  
- **Unicode Support**: Improved in PCRE2 for handling modern text encoding standards.  

### Distribution and Packaging  
- **Linux**: Available via package managers (`pcre`, `pcre2` in Debian, Fedora, Arch Linux).  
- **Windows**: Compatible with native and cross-platform development tools.  

### Community and Documentation  
- **Source Code**: Hosted on GitHub ([PCRE2Project/pcre2](https://github.com/PCRE2Project/pcre2)).  
- **User Manuals**: Provided in English on the official website and GitHub repository.  

### Licensing  
- **3-clause BSD License**: Allows free use, modification, and redistribution with minimal restrictions.  

--- 

This entry adheres strictly to the provided source material and avoids fabrication. Let me know if you'd like any refinements!

## References

1. [Source](http://www.pcre.org/licence.txt)
2. [Source](https://lists.exim.org/lurker/message/20150105.162835.0666407a.en.html)
3. [Source](https://lists.exim.org/lurker/message/20150702.132654.bc9e824f.en.html)
4. [Source](https://lists.exim.org/lurker/message/20160112.145451.15f6d597.en.html)
5. [Source](https://lists.exim.org/lurker/message/20160729.085606.41239029.en.html)
6. [Source](https://lists.exim.org/lurker/message/20170214.105056.99ec8e5c.en.html)
7. [Source](https://lists.exim.org/lurker/message/20170815.110754.c6ecc65a.en.html)
8. [Source](https://lists.exim.org/lurker/message/20180212.114146.6c7b2407.en.html)
9. [Release pcre2-10.32 Historic release · PCRE2Project/pcre2. 2022](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.32)
10. [Source](https://lists.exim.org/lurker/message/20190416.154043.a260ee6c.en.html)
11. [PCRE1 release 8.43 is available](https://lists.exim.org/lurker/message/20190223.165009.b0fb3c20.en.html)
12. [Source](https://lists.exim.org/lurker/message/20191121.163527.4dedd295.en.html)
13. [Source](https://lists.exim.org/lurker/message/20200212.174850.6edd8277.en.html)
14. [Source](https://lists.exim.org/lurker/message/20200509.155508.781af24f.en.html)
15. [Release of 10.37](https://lists.exim.org/lurker/message/20210526.143809.5258b1c7.en.html)
16. [Source](https://lists.exim.org/lurker/message/20150306.151512.10827001.en.html)
17. [Release pcre2-10.39. 2021](https://github.com/PhilipHazel/pcre2/releases/tag/pcre2-10.39)
18. [10.39 is now released. 2021](https://groups.google.com/g/pcre2-dev/c/xjDeQS1MH6s)
19. [Final release of PCRE1. 2021](https://lists.exim.org/lurker/message/20210615.162400.c16ff8a3.en.html)
20. [2022](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.40)
21. [Release 10.36. 2022](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.36)
22. [Release 10.38. 2021](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.38)
23. [Release 10.41. 2022](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.41)
24. [Release 10.42. 2022](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.42)
25. [Release PCRE2-10.43](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.43)
26. [Release 10.44. 2024](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.44)
27. [Release PCRE2-10.45 · PCRE2Project/pcre2](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.45)
28. [Release 10.46. 2025](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.46)
29. [Release 10.47. 2025](https://github.com/PCRE2Project/pcre2/releases/tag/pcre2-10.47)
30. Freebase Data Dumps. 2013