Cleaning up your path in PowerShell, and adding stuff to it.

A while back, I demonstrated some PowerShell one-liner-fu for path management. I also pointed out that my machine had duplicate entries in its path. Most people would not care about this at all. Most of the few people that do care would cleanup their path by hand. However, there are a mentally deranged few who realize the world needs a PowerShell script to clean up our paths for us. Luckily for you, I am that kind of crazy. However, I don’t stop there. I also show you how to search the registry to add items to your path.

Warning: I don’t know much about PowerShell and I’ve not tested this script nearly enough. This thing messes with your system path, and things can go really bad if you run it and it messes up your path. Be very careful running it. If you run it your the fool who follows a fool, which makes you Han Solo, not Ben Kenobi. However, your shooting your %PATH% not Greedo.

The script makes use of multi dimensional arrays and foreach loops. I’d be lying if i said that it was efficiently written or bug free. However, it works and does a few clever things with PowerShell.

So with that out of the way, the script is located in a github repository in our newly created github organization I mentioned before. The script is called Path-Fixer.ps1. It is available under the MIT license. I hope to improve it as time goes on. If you fork it and improve the script, please send us a pull request.

Notes about this script

Your path is a combination of two Environment variables. Those are the machine %PATH% and the user %PATH%. My script only concerns itself with the machine level path. Therefore I don’t use $ENV:PATH, like I do in my one-liner example to get the original path. Instead I use [Environment]::GetEnvironmentVariable(‘PATH’, ‘machine’).

Another thing I do is trim off trailing slashes at the end of the path. This means C:\windows\ becomes C:\windows. This may seem like excess, but it also allows me to remove duplicates that only differ because one has a trailing path, and one lacks it.

Two other caveats exist with regard to comparison. One is differences in case. Luckily, String.Replace() is case insensitive by default so my script handles it. The other is environment variable expansion. On windows if you stick %SYSTEMROOT%\system32 in your path, the OS will expand that to c:\windows\system32. My script does not handle this at the moment. Hopefully it will in the future.

I have some very simple registry detection to detect if a few programs are installed. This will probably remain a hard coded list of programs, and registry entries that determine the installation path. I’m hoping to also add detection through windows services. This would be good for something like mongodb that lacks an installer, but can self install as a windows service.

Finally, I’d like to point out that the script is UTF-16 encoded. This is simply because I wrote it script in PowerShell ISE, which decided to save it in UTF-16 format. Rather than change it to UTF-8 so git could easily diff it, I decided to fix git. This stackoverflow question provided the guidance I needed.


Once again, I’d like to reiterate that you must be careful when using this script. There might be some serious bugs, and messing with your path can lead to bad things happening. Also, while I will probably blog about updates to the script, the fastest way to keep track of its changes is to look at the github commit notes, and the source code itself. Finally, if you find a bug in my script or make and improvement, patches will be accepted, and due credit given.