Allows switching between different versions of Terraform on Windows, similar to TFSwitch or tfenv.

Set-TerraformVersion.ps1

function Set-TerraformVersion {
        param(
        [string]$version
    )

    # Constants
    $BaseUrl = "https://releases.hashicorp.com/terraform"
    $UsageInfo = "Usage: Set-TerraformVersion <VERSION>`n Example: Set-TerraformVersion 0.14.11`n Or you can specify 'latest' to get the latest version"

    if([string]::IsNullOrEmpty($version)) {
        Write-Output $UsageInfo
        return
    }

    $tfVersion
    $response = Invoke-WebRequest $BaseUrl
    $content = $response.Content.Split([Environment]::NewLine)
    $versionMatches = ($content | Select-String -Pattern "/[.0-9]+/" -AllMatches).Matches
    $versions = $versionMatches.Value -replace "/"
    $sorted = $versions | Sort-Object {[Version] $_} -Descending
    if($version.ToLower() -eq "latest") {
        $tfVersion = $sorted[0]
    } else {
        $versionString = Get-NormalizedVersion($version)
        $specificMatches = $sorted.where{$_ -match "^$versionString"}

        if($specificMatches.Count -eq 0) {
            Write-Output "No versions were found that match your input. Check that your input is not too specific.`nAlso make sure the version you are asking for either still exists or has been released."
            return
        }
        
        $tfVersion = $specificMatches[0]
    }

    $tfPath = (Get-Command -Name terraform -ErrorAction SilentlyContinue)
    if($null -eq $tfPath) {
        Write-Output "Terraform is not currently installed, install a version first to continue."
        return
    } else {
        $versionText = (terraform version)[0]

        if ($versionText.Where{$_ -match "v$tfVersions$"}) {
            Write-Output "This version is already installed. Exiting without downloading anything..."
            return
        }
    }
    $TargetUrl = "${BaseUrl}/${tfVersion}/terraform_${tfVersion}_windows_amd64.zip"

    Write-Output "Downloading and switching to Terraform version ${tfVersion}"
    Write-Output "Please wait..."

    if(!(Test-Path ~/tmp)) {
        New-Item -ItemType Directory -Path ~/tmp | Out-Null
    }
    Push-Location
    Set-Location -Path ~/tmp

    Invoke-WebRequest ${TargetUrl} -OutFile "terraform_${tfVersion}_windows_amd64.zip"
    Expand-Archive -Path "terraform_${tfVersion}_windows_amd64.zip" 

    Move-Item -Path "terraform_${tfVersion}_windows_amd64/terraform.exe" -Destination $tfPath.Source -Force
    $newVersion = (terraform version)[0]

    Write-Output "You are now using $newVersion"
    Pop-Location

    Remove-Item -Path ~/tmp -Recurse -Force
}

function Get-NormalizedVersion {
    param (
        [string] $versionString
    )

    if (-not $versionString.EndsWith(".")) {
        $versionString = "$versionString."
    }

    return $versionString
}