Basic Powerline-like PowerShell prompt. Save to `$PROFILE.AllUsersAllHosts`.

profile.ps1

# Note: requires a Powerline-patched font to display properly
# See https://github.com/powerline/fonts
$CURRENT_BG = $null
$SEGMENT_DELIMETER_GLYPH = ""
$GIT_BRANCH_GLYPH = ""

function prompt {
    Write-PowerlineUserContext
    Write-PowerlineLocation
    Write-PowerlineGit
    Write-PowerlineSegmentEnd

    # Required to prevent the default "PS>" since we use Write-Host to get colors
    return " "
}

Function Write-PowerlineSegment($bg = 'Black', $fg = 'Blue', $str) {
    if ($CURRENT_BG -and $CURRENT_BG -ne $bg) {
        Write-Host "$SEGMENT_DELIMETER_GLYPH" -ForegroundColor $CURRENT_BG -BackgroundColor $bg -NoNewline
    }
    
    $Global:CURRENT_BG = $bg
    Write-Host " $str " -ForegroundColor $fg -BackgroundColor $bg -NoNewline
}

Function Write-PowerlineSegmentEnd() {
    Write-Host "$SEGMENT_DELIMETER_GLYPH" -ForegroundColor $CURRENT_BG -BackgroundColor Black -NoNewline
    $Global:CURRENT_BG = $null
}

Function Write-PowerlineUserContext() {
    if (Test-Administrator) {
        Write-PowerlineSegment -bg Red -fg Black "${env:UserName}"
    }
    else {
        Write-PowerlineSegment -bg Green -fg Black "${env:UserName}"
    }
}

Function Write-PowerlineLocation() {
    Write-PowerlineSegment -bg Blue -fg Black -str "$pwd"
}

Function Write-PowerlineGit() {
    if (Get-Command git -ErrorAction SilentlyContinue) {
        if ($(git rev-parse --is-inside-work-tree 2>$null)) {
            $branch = $(git symbolic-ref HEAD 2>$null).ToString().Substring(11)
            Write-PowerlineSegment -bg Yellow -fg Black -str "$GIT_BRANCH_GLYPH $branch"
        }
    }
}

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

Function Initialize-Host {
    $bg = $Host.UI.RawUI.BackgroundColor
    $Host.PrivateData.ErrorBackgroundColor = $bg
    $Host.PrivateData.WarningBackgroundColor = $bg
    $Host.PrivateData.DebugBackgroundColor = $bg
    $Host.PrivateData.VerboseBackgroundColor = $bg
    $Host.UI.RawUI.WindowTitle = "Windows PowerShell v$($PSVersionTable.PSVersion.Major).$($PSVersionTable.PSVersion.Minor)"
}

Initialize-Host