Regular Expressions are an industry-standard text pattern matching syntax. By using Regular Expressions, you can quickly interact with text strings to either change what they look like (using the REGEXREPLACE function) or test to see if they contain a specific sub-string (using the REGEXMATCH function).
Insight leverages the Microsoft .NET support for Regular Expressions.
For more information about regular expressions, TIBCO suggests that you do an internet search on the phrase Microsoft Regular Expressions to find useful resources.