Understanding the eight Powershell profiles (or Nobody expects the Spanish Inquisition)
A while ago, I started using the Windows Powershell ISE, and immediately fell foul of the fact that the scripts I was debugging didn't work because their environment was set up in my $profile. It turns out that the ISE has a separate profile from the one used in the PowerShell proper. It's easy enough to deal with once you know about this, although my first attempt of at working round the problem would have been better if I'm known how easy it is to get the names of the different profile locations. At that time, things would have gone better if I'd have first read this article by Ed Wilson on the Scripting Guy blog: Understanding the Six Powershell Profiles.
In this article, he explains that there are four profiles which are loaded by the PowerShell on startup. You can get the names of them by looking at the $profile variable. The commonest use of this is to do something like:
to edit your profile. Well as you already know by this point, there are more. You can see these with a little more typing, as follows:
$profile.CurrentUserAllHosts $profile.CurrentUserCurrentHost $profile.AllUsersCurrentHost $profile.AllUsersAllHosts
What you get when you type $profile is the same as $profile.CurrentUserCurrentHost.
So that's four. You can get to quite easily by understanding that the ISE and the PowerShell are different hosts, so are entitled to specify their own locations for the CurrentHost versions. Of course, having got that far, we can immediately suppose that any application that hosts the PowerShell might also have it's own CurrentHost profiles, so in theory it's limitless. Whatever... I don't have any beef with Ed for saying there are six - he was describing the general case, and doing a good job of helping people avoid a slightly non-obvious pitfall. (Like I said - I wish I'd read his article earlier than I did.)
So there you have it. We can say eight, ten, twelve... whatever.. so what's the point of this blog post? Well it turns out that I managed to uncover a different non-obvious pitfall. Drove me crazy for a while, I can tell you!
I quite often use Vim for text editing, and I thought it would be cool to get it wired up to work with PowerShell. I already had PowerShell syntax highlighting set up, but I wanted to be able to open up files and edit them from within the shell. There's plenty of material on the Internet about how to do this, and I set to with a will. Not too hard - set up a couple of aliases and so forth. But then I found that when I opened up files directly in the shell (instead of spawning the a gVim window) the syntax highlighting combined with the background color of the shell was just awful. If I am in an elevated shell, I have this set to DarkRed, and the code to do this is in my profile. So I went to disable it. Looked in my profile. The colour changing code wasn't there. Then I remembered the other profiles - and that I'd put this code into one of the AllUsers profiles, or at least I thought I had - because it wasn't there either. Well it was definitely executing. If I started the powershell with -noprofile, I got a dark blue background, and without -noprofile, I got red. Hmm... Then I edited all four profiles so that each would emit it's name when executed. Nothing doing! The AllUsers profiles weren't even executing.
Eventually I poked at it some more, and realised that if I used notepad to edit the AllUsers profiles, I could see my colour changing code, but from vi I saw my "This is the AllUsersCurrentHost profile" line. Bingo! You've probably guessed by now. It was a 64bit server, and as the AllUsers profiles are down in C:\Windows\System32, they are mirrored in C:\Windows\SysWOW64\. It therefore depends on whether you are using a 32 bit or 64 bit editor.
So according to Ed's counting system, the total is now eight!