function prompt{
$p = Split-Path (
Get-Location
) -Leaf
git branch | foreach{
if($_ -match "^*(.*)"){
$p += " [" + $matches[1] + " ] "
}
}
$p = $p + ">"
Write-Host $p -NoNewline -ForegroundColor Green
return " "
}
Adicione a função acima no arquivo $ PROFILE. Salve e reinicie o Powershell.
Fonte: http://veerasundar.com/blog/2013/05/customize-powershell-prompt-message/