Windows PowerShell 2.0 Profile that adds a descriptive prompt suitable for working with git (or hg) and virtualenvs

profile.ps1

# Written by Donald Stufft
#
# My Windows PowerShell Profile. It gives a prompt that looks like
# UserName at MachineName in ~/path on master^1?!
# (virtualenvname) ± 
#
# Explanation:
#     If you are in a git repo the prompt character will be ±, ¥ for mercurial and » otherwise.
#     If you are in a git repo it will include the "on ...." bit.
#         It will replace master with the name of the current branch
#         It will include ^# where # is how many commits ahead of origin you are
#         It will include ? if you have untracked files and ! if you have uncommited changes
#     If you are using virtualenvs then the current
#         virtualenv name will appear in front of the prompt character inside of () 

$GIT_PROMPT_PREFIX = " on "
$GIT_PROMPT_SUFFIX = ""
$GIT_PROMPT_DIRTY  = "!"
$GIT_PROMPT_UNTRACKED = "?"
$GIT_PROMPT_CLEAN = ""
$GIT_PROMPT_AHEAD = "^"

$THEME_COLOR_USERNAME = [ConsoleColor]::Magenta
$THEME_COLOR_HOST = [ConsoleColor]::Yellow
$THEME_COLOR_PATH = [ConsoleColor]::Green
$THEME_COLOR_BRANCH = [ConsoleColor]::Magenta
$THEME_COLOR_AHEAD_PREFIX = [ConsoleColor]::White
$THEME_COLOR_AHEAD_TEXT = [ConsoleColor]::Magenta
$THEME_COLOR_DIRTY = [ConsoleColor]::Red
$THEME_COLOR_UNTRACKED = [ConsoleColor]::Blue
$THEME_COLOR_CLEAN = [ConsoleColor]::White
$THEME_COLOR_VIRTUALENV_INFO_WRAP = [ConsoleColor]::White
$THEME_COLOR_VIRTUALENV_INFO_TEXT = [ConsoleColor]::White

Import-Module virtualenvwrapper

function shorten-path([string] $path)
{ 
   return $path.Replace($HOME, '~').Replace("\", "/")
}

function git-prompt-info
{
	if (Get-Command "git" -errorAction SilentlyContinue)
	{
		$ret = ""
		
		$ref=$(git symbolic-ref HEAD)
		if (!$ref) { return "" }
		
		Write-Host($GIT_PROMPT_PREFIX) -n
		Write-Host($ref -replace "refs/heads/", "") -n -f $THEME_COLOR_BRANCH
		Write-Host($(git-prompt-ahead)) -n
		Write-Host($(git-prompt-status)) -n
		Write-Host($GIT_PROMPT_SUFFIX) -n
	}
	
	return ""
}

function git-prompt-ahead
{
	if (Get-Command "git" -errorAction SilentlyContinue)
	{
		$GITSTATUS = $(git status)
		
		if ($GITSTATUS)
		{
			$AHEAD = [string]$($GITSTATUS | select-string "^# Your branch is ahead of")
			if ($AHEAD)
			{
				$AHEAD = $AHEAD.SubString(0, $AHEAD.LastIndexOf(" "))
				$AHEAD = $AHEAD.SubString($AHEAD.LastIndexOf(" ") + 1)
				Write-Host($GIT_PROMPT_AHEAD) -n -f $THEME_COLOR_AHEAD_PREFIX
				Write-Host($AHEAD) -n -f $THEME_COLOR_AHEAD_TEXT
			}
		}
	}
	
	return ""
}

function git-prompt-status
{
	if (Get-Command "git" -errorAction SilentlyContinue)
	{
		$GITSTATUS = $(git status --porcelain)
		
		if (!$GITSTATUS)
		{
			Write-Host($GIT_PROMPT_CLEAN) -n -f $THEME_COLOR_CLEAN
		}
		else
		{
			if ($GITSTATUS | select-string ^??)
			{
				Write-Host($GIT_PROMPT_UNTRACKED) -n -f $THEME_COLOR_UNTRACKED
			}
			if ($GITSTATUS | select-string "^ ?[MADRCU]")
			{
				Write-Host($GIT_PROMPT_DIRTY) -n -f $THEME_COLOR_DIRTY
			}
		}
	}
	
	return ""
}

function virtualenv-info
{
	if($env:VIRTUAL_ENV)
	{
		Write-Host("(") -n -f $THEME_COLOR_VIRTUALENV_INFO_WRAP
		Write-Host($(split-path $env:VIRTUAL_ENV -leaf)) -n -f $THEME_COLOR_VIRTUALENV_INFO_TEXT
		Write-Host(") ") -n -f $THEME_COLOR_VIRTUALENV_INFO_WRAP
	}
	return ""
}

function prompt-char
{
	if (Get-Command "git" -errorAction SilentlyContinue)
	{
		git branch > $null
		if ($?) { return "± " }
	}
	
	if (Get-Command "hg" -errorAction SilentlyContinue)
	{
		hg root > $null
		if ($?) { return "¥ " }
	}
	
	return "» "
}

function prompt
{
	Write-Host ("")
	Write-Host ([Environment]::UserName) -n -f $THEME_COLOR_USERNAME
	Write-Host (" at ") -n
	Write-Host ([Environment]::MachineName) -n -f $THEME_COLOR_HOST
	Write-Host (" in ") -n
	Write-Host (shorten-path (pwd).PATH) -n -f $THEME_COLOR_PATH
	Write-Host (git-prompt-info)
	
	Write-Host (virtualenv-info) -n
	return $(prompt-char)
}