Huddled Masses

Posts Tagged ‘CurrentDirectory’

For this edition of my Power User tips for PowerShell, I’m going to share my (heavily annotated) prompt function. Feel free to to copy useful pieces or just place the whole thing in your profile script I’m not going to say anything more, I’ll let the comments speak for themselves.

Edit: Someone just pointed out that I forgot the bit of my prompt that sets my current path into the window title, and I realized I also forgot the bit that puts (Admin) in the title if you’re running “elevated” on Vista.

[new] Edit: Ok, how many people noticed that I incorrectly used the Environement.CurrentDirectory when I set the WindowTitle (meaning it would only work right in FileSystem drives)? Fixed now.

This is the second in an occasional series of tips for PowerShell users: short posts which don’t intend to give guidance, but merely a tip on a feature you may not be aware of, or maybe even answers to some of the recurring questions that come up in #PowerShell.

Fixing the “Current Directory” problem

The core of this tip is very simple: Windows tracks your application’s “current directory” ... and you can get and set this location using static methods of the System.IO.Directory class: SetCurrentDirectory and GetCurrentDirectory.

The reason this is showing up as a Power User Tip is that PowerShell doesn’t set this environment setting when you navigate — it uses it’s internal “PSProvider” architecture, and doesn’t differentiate between whether you’re in a FileSystem location or a registry location, or even a third-party provider. So, it never actually changes the current directory, and any console command or .net method you call which uses the current directory will most likely be in the wrong place — like, for instance:

The problem is that now you don’t know where “NeatFile.txt” is — the “current directory” depends on how you launched PowerShell — most frequently it’s your $Home directory (equivalent to Env:HOMEDRIVE + Env:HOMEPATH — usually something like C:\Documents and Settings\YourName), but it could be your SystemRoot (C:\Windows) or the current directory of the app that launched PowerShell (eg: C:\Windows\System32 when you run it via “runas”). You can figure it out by running: [IO.Directory]::GetCurrentDirectory().

But here’s something more interesting: you can “fix” the problem by using [IO.Directory]::SetCurrentDirectory. There are a couple of catches, however: You can’t just use $pwd or Get-Location because you might be in the registry or some other location that’s not a Directory. And you can’t just use Get-Location -PSProvider FileSystem because even though it returns the current FileSystem provider path, the FileSystem provider supports “fake” PSDrives (eg: you could create a Scripts: drive like new-psdrive scripts filesystem "$Home\Scripts") and these aren’t actually supported by the .Net FileSystem. Luckily, PowerShell includes a Convert-Path cmdlet which was created for this very purpose: converting a path from a Windows PowerShell path to a native path supported by the underlying provider.

Without further ado, here’s a one-liner you can add to your prompt function:

[new] Edit: You can do the same thing using the System.Environment class, and it turns out that the ProviderPath is a property of the PathInfo object, perhaps you’ll find this syntax simpler: