Update for PowerShell 6

Update for PowerShell 6 (Core) and add cross platform support. Currently the "prompt" function set by Posh-Git in PowerShell Core is a little bugged, but I'm sure they will fix it soonish.

Author: Klaus Frank

book/A-git-in-other-environments/sections/powershell.asc

@@ -3,15 +3,15 @@
 
 (((powershell)))(((tab completion, powershell)))(((shell prompts, powershell)))
 (((posh-git)))
-The legacy command-line terminal on Windows (`cmd.exe`) isn't really capable of a customized Git experience, but if you're using Powershell, you're in luck.
+The legacy command-line terminal on Windows (`cmd.exe`) isn't really capable of a customized Git experience, but if you're using Powershell, you're in luck. This also works if you're running PowerShell on any other platform than Windows like Debian.
 A package called Posh-Git (https://github.com/dahlbyk/posh-git[]) provides powerful tab-completion facilities, as well as an enhanced prompt to help you stay on top of your repository status.
 It looks like this:
 
 .Powershell with Posh-git.
 image::images/posh-git.png[Powershell with Posh-git.]
 
 ==== Installation
-===== Prerequisites
+===== Prerequisites (Windows only)
 Before you're able to run PowerShell scripts on your machine, you need to set your local ExecutionPolicy to RemoteSigned (Basically anything except Undefined and Restricted). If you choose AllSigned instead of RemoteSigned, also local scripts (your own) need to be digitally signed in order to be executed. With RemoteSigned, only Scripts having the "ZoneIdentifier" set to Internet (were downloaded from the web) need to be signed, others not.
 If you're an administrator and want to set it for all Users on that machine, use "-Scope LocalMachine".
 If you're a normal user, without administrative rights, you can use "-Scope CurrentUser" to set it only for you.
@@ -28,16 +28,19 @@ If you have at least PowerShell 5 or PowerShell 4 with PackageManagement install
 More information about the requirements: (https://docs.microsoft.com/en-us/powershell/gallery/psget/get_psget_module[])
 [source,powershell]
 -----
+> Set-PSRepository -Name PSGallery -InstallationPolicy Trusted
 > Update-Module PowerShellGet -Force
 > Install-Module Posh-Git -Scope AllUsers
 -----
-If you want to install Posh-Git only for the currnet user and not globaly, use "-Scope CurrentUser" instead.
+If you want to install Posh-Git only for the currnet user and not globaly, use "-Scope CurrentUser" instead. 
+If the 2nd command fails with the message `Update-Module : Module 'PowerShellGet' was not installed by using Install-Module, so it cannot be updated.` You need to run: `Install-Module PowerShellGet -Force -SkipPublisherCheck` instead. This happens, because the modules that ship with Windows Powershell are signed with a different publishment certificate.
 
 ===== Update PowerShell Prompt
 To include git information in your prompt, posh-git needs to be imported. To do this automatically, include the import statement into you $profile script. This script is executed everytime you open a new PowerShell prompt.
 Keep in mind, that there are multiple $profile scripts. E. g. one for the console and a separate one for the ISE.
 [source,powershell]
 -----
+> New-Item -Name $(Split-Path -Path $profile) -ItemType Directory -Force
 > 'Import-Module Posh-Git' | Out-File -Append -Encoding default -FilePath $profile
 -----