Microsoft.PowerShell_profile.ps1

function which {
    (Get-Command $args).Source
}

function whoami {
    echo $Env:UserName
}

function prompt {
  $currentPrincipal = New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())
  Write-Host -NoNewline "$Env:username@$Env:computername" -ForegroundColor Green
  Write-Host -NoNewline ":"
  Write-Host -NoNewline -ForegroundColor Blue ("$PWD".StartsWith("$HOME") ? ("~"+"$PWD".Substring("$HOME".Length)) : ("$PWD".StartsWith("C:\") ? "$PWD".Substring(2) : $PWD))
  Write-Host -NoNewline ($currentPrincipal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator) ? "#" : "$")
  return " "
}