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Regular Expression Info and Tips for Powershell

One of the most useful tools a scripter has at their disposal is Regular Expressions. The problem is that regular expressions can seem like Greek and for most folks learning them can seem an impossible task. I hope this blog post provides those people some hope as well as some tools they can use to tackle this mountain one foot at a time.

NOTE: I would like to make this blog entry as dynamic as possible, so if you have your own tips… let me know and I will add them.

Everyone is different, but this is how I went about learning Regular Expressions

  • Phase one: Learn EXACTLY what a regular expression is and what it can and can NOT do.
  • Phase two: Learn the syntax. I printed out the RegEx Cheet Sheet and use it daily.
  • Phase three: Find a purpose. I find if I actually have a problem I spend more energy on learning.
  • Phase four: Create a simple Regular Expression.
  • Phase five: Build on your Regular Expression.
  • Phase six: Trouble shooting the Regular Expression.

Useful Tips:

  • First things first… Click here and watch the vids
  • Keep a cheat sheet close at hand!
  • Take them in small bites. I hope to blog in detail about this later, but lets just say string concatenation is your friend
  • Keep it simple!
  • $matches is your friend! $matches is an object that Powershell creates when you make a RegEx call (like -match.)
  • Google It. Chances are there is Regex already out there for what you need.
  • Using Lables can save you time by extracting certain data and making it a property on $matches.
  • RichardP from IRC says “Dont eat yellow snow?” Apparently he has experience in this area.

Online Vids:
This is GREAT stuff provided by Shay (aka scriptfanatic)

Good Blog Entries:
MoW at it again.

RegEx Cheet Sheet (my Favorite)
Regular Expression Library

Online Regex Checkers:
RegEx Tester (my Favorite)
Regular Expression Library Tester

Mastering Regular Expressions (my Favorite)
Regular Expression Recipes for Windows Developers

RegEx Buddy

One Response to “Regular Expression Info and Tips for Powershell”

  1. on 12 Jan 2009 at 10:20 amJason Archer

    I have also liked using Regex Coach:

    It is nice for checking if and when a regex is matching something. It is fast and easy to use (though no design mode).

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