VS 2017 PowerShell script; if you need invoke-cmdscript, it's here: https://gist.github.com/bradwilson/3fca203370d54304eff1cce21ffc32aa

vs2017.ps1

param(
    [string]$edition,
    [switch]$noWeb = $false
)

# Try and find a version of Visual Studio in the expected location, since the VS150COMNTOOLS environment variable isn't there any more
$basePath = join-path (join-path ${env:ProgramFiles(x86)} "Microsoft Visual Studio") "2017"

if ((test-path $basePath) -eq $false) {
    write-warning "Visual Studio 2017 is not installed."
    exit 1
}

if ($edition -eq "") {
    $editions = (get-childitem $basePath | where-object { $_.PSIsContainer })
    if ($editions.Count -eq 0) {
        write-warning "Visual Studio 2017 is not installed."
        exit 1
    }
    if ($editions.Count -gt 1) {
        write-warning "Multiple editions of Visual Studio 2017 are installed. Please specify one of the editions ($($editions -join ', ')) with the -edition switch."
        exit 1
    }
    $edition = $editions[0]
}

$path = join-path (join-path (join-path $basePath $edition) "Common7") "Tools"

if ((test-path $path) -eq $false) {
    write-warning "Visual Studion 2017 $edition could not be found."
    exit 1
}

$cmdPath = join-path $path "VsDevCmd.bat"

if ((test-path $cmdPath) -eq $false) {
    write-warning "File not found: $cmdPath"
    exit 1
}

invoke-cmdscript $cmdPath

if ($noWeb -eq $false) {
    $path = join-path (join-path (join-path $basePath $edition) "Web") "External"

    if (test-path $path) {
        $env:Path = $env:Path + ";" + $path
    } else {
        write-warning "Path $path not found; specify -noWeb to skip searching for web tools"
    }
}

vspreview.ps1

param(
    [string]$edition,
    [switch]$noWeb = $false
)

$basePath = join-path (join-path ${env:ProgramFiles(x86)} "Microsoft Visual Studio") "Preview"

if ((test-path $basePath) -eq $false) {
    write-warning "Visual Studio Preview is not installed."
    exit 1
}

if ($edition -eq "") {
    $editions = (get-childitem $basePath | where-object { $_.PSIsContainer })
    if ($editions.Count -eq 0) {
        write-warning "Visual Studio Preview is not installed."
        exit 1
    }
    if ($editions.Count -gt 1) {
        write-warning "Multiple editions of Visual Studio 2017 are installed. Please specify one of the editions ($($editions -join ', ')) with the -edition switch."
        exit 1
    }
    $edition = $editions[0]
}

$path = join-path (join-path (join-path $basePath $edition) "Common7") "Tools"

if ((test-path $path) -eq $false) {
    write-warning "Visual Studion Preview $edition could not be found."
    exit 1
}

$cmdPath = join-path $path "VsDevCmd.bat"

if ((test-path $cmdPath) -eq $false) {
    write-warning "File not found: $cmdPath"
    exit 1
}

invoke-cmdscript $cmdPath

if ($noWeb -eq $false) {
    $path = join-path (join-path (join-path $basePath $edition) "Web") "External"

    if (test-path $path) {
        $env:Path = $env:Path + ";" + $path
    } else {
        write-warning "Path $path not found; specify -noWeb to skip searching for web tools"
    }
}