PowerShell profile

Microsoft.PowerShell_profile.ps1

function Get-HomeLocation {
	# Using 'Run as administrator' does not set $Home, so try other variables as well
	if ($variable:Home) {
		$variable:Home
	} elseif ($env:Home) {
		$env:Home
	} elseif ($env:UserProfile) {
		$env:UserProfile
	} else {
		$null
	}
}

function Get-HomeRelativeLocation
{
	$h = Get-HomeLocation
	if ($h) {
		$pwd = [string] (Get-Location)

		if ($pwd.StartsWith($h)) {
			'~' + $pwd.Substring($h.Length)
		} else {
			$pwd
		}
	} else {
		[string] (Get-Location)
	}
}

function Write-LabeledPrompt ($Label)
{
	if ($nestedpromptlevel -ge 1) {
		'>>> '
	} else {
		$pwd = Get-HomeRelativeLocation

		if (Test-Administrator) {
			Write-Host -NoNewline -ForegroundColor Red "[Admin] "
		}

		if (Test-Path variable:/PSDebugContext) {
			Write-Host -NoNewline -ForegroundColor DarkGreen '[DBG]:'
		}

		Write-Host -NoNewline -ForegroundColor DarkGreen "$Label "
		Write-Host -ForegroundColor DarkYellow ('[' + $pwd + ']')

		'> '
	}
}

function prompt
{
	Write-LabeledPrompt 'PS'
}

function Test-Administrator
{
	$user = [Security.Principal.WindowsIdentity]::GetCurrent()
	(New-Object Security.Principal.WindowsPrincipal $user).IsInRole([Security.Principal.WindowsBuiltinRole]::Administrator)
}

function touch {
    param([string] $filename)
    New-Item -type file $filename
}

# If the file system has not had its home set (eg using run as administrator) try to set
# it using one of the other environmental variables so that commands like 'cd ~' work
if (-not (Get-PSProvider 'FileSystem').Home) {
	$h = Get-HomeLocation
	if ($h) {
		(Get-PSProvider 'FileSystem').Home = $h
	}
}

Beautiful. I spent WAY more time on this (Run-as-admin doesn't set $HOME or ~) at home last night than I should have. Nice to know I'm not insane. Maybe I missed the env: prefix on $UserProfile.