Regular Expression (regex) Tutorial

I thought I would put out a great document that was created almost a decade ago involving Regular Expressions (regex). If anyone is interested, you can view the tutorial:

• Regular Expression Tutorial pg1
• Different Regular Expression Engines pg 2
• Literal Characters pg 3
• Special Characters pg 4
• Non-Printable Characters pg 5
• First Look at How a Regex Engine Works Internally pg 6
• Character Classes or Character Sets pg 7
• The Dot Matches (Almost) Any Character pg 8
• Start of String and End of String Anchors pg 9
• Word Boundaries pg 10
• Alternation with the Vertical Bar or Pipe Symbol pg 11
• Optional Items pg 12
• Repetition with Star and Plus pg 13
• Grouping with Round Brackets pg 14
• Named Capturing Groups pg 15
• Unicode Regular Expressions pg 16
• Regex Matching Modes pg 17
• Possessive Quantifiers pg 18
• Understanding Atomic Grouping in Regular Expressions pg 19
• Understanding Lookahead and Lookbehind in Regular Expressions (Lookaround) pg 20
• Testing Multiple Conditions on the Same Part of a String with Lookaround pg 21
• Understanding the \G Anchor in Regular Expressions pg 22
• Using If-Then-Else Conditionals in Regular Expressions pg 23
• XML Schema Character Classes and Subtraction Explained pg 24
• Understanding POSIX Bracket Expressions in Regular Expressions pg 25
• Adding Comments to Regular Expressions: Making Your Regex More Readable pg 26
• Free-Spacing Mode in Regular Expressions: Improving Readability pg 27