Regex tutorial for people who should know Regex, but do not.. Part 1. Part 1 | Part 2 Regular expressions are very useful. If you have to deal with text at all, you will find them indispensable. In programming, they can be used to verify user input (e.g check an email is valid), sanitize input (make sure the user only used allowed characters), remove sections of the string (remove all non-alpha-numeric characters).
And not just for programming! You can use regular expressions in many text editors to edit the current file. As you can tell from the previous paragraph, they are very versatile. Regular Expressions (regex for short) are really very simple.. [set of characters]{number of characters to match} For example, [a-z]{2} will match two letters, from a-z. In the previous [a-z] is the characters to look for, {2} is how many characters to match. ..that's it! Character sets Now, lets say you would to match more than just a-z. [a-zA-Z0-9?]
You can add different ranges or characters to the [ ] character-class. But.. say you want to match the ] symbol too! [a-z]{2} Crucial Concepts Behind Advanced Regular Expressions | How-To ... PowerGREP - Windows Grep - Regex Search and Replace. While all of PowerGREP's functionality is also available from the command line, the key benefit of PowerGREP over the traditional grep is its flexible and convenient graphical interface. Instead of just listing the matching lines, PowerGREP will also highlight the actual matches and make them clickable. When you click on a match, PowerGREP will load the file, with syntax coloring, allowing you to easily inspect the context of a match. PowerGREP also provides a full-featured multi-line text editor box for composing the regular expression you want to use in your search. PowerGREP's regex flavor supports all features of Perl 5, Java and .NET.
The Ultimate Search and Replace If you already have some experience with regular expressions, then you already know that searching and replacing with regular expressions and backreferences is a powerful way to maintain all sorts of text files. Another benefit is PowerGREP's ability to work with lists of regular expressions. Make a Donation. Strfriend. RegExr: Online Regular Expression Testing Tool.