All the programming and scripting languages have built-in support for regular expressions these days. The basic rules to define and execute regular expressions are pretty much the same across all the languages. However, these regex implementations have their own flavors that differ from each other at the advanced level. We will cover regular expressions using Java in this book.

Some of the popular flavors of regular expressions are as follows:

• .NET
• Java
• Perl
• PCRE (PHP)
• JavaScript
• VBScript
• Python
• R
• Ruby
• std::regex
• boost::regex
• Basic Regular Expressions (BRE) - used by Unix utilities ed, vi, sed, grep, and so on
• Extended Regular Expressions (ERE) - used by Unix utilities sed, grep, awk, and so on