Add -g flag for global system install

README.md

@@ -93,6 +93,14 @@ brew install protobuf # macOS
 cargo install deno
 ```
 
+## Install Globally
+
+**With PowerShell:**
+
+```powershell
+$denoGlobalInstall; irm https://deno.land/install.ps1 | iex
+```
+
 ## Install and Manage Multiple Versions
 
 **With [asdf](https://asdf-vm.com) and [asdf-deno](https://github.com/asdf-community/asdf-deno):**
@@ -178,3 +186,4 @@ During the `install.sh` process, `unzip` or `7z` is used to extract the zip arch
 **How can this issue be fixed?**
 
 You can install unzip via `brew install unzip` on MacOS or `apt-get install unzip -y` on Linux.
+

install.ps1

@@ -4,16 +4,17 @@
 
 $ErrorActionPreference = 'Stop'
 
-if ($v) {
-  $Version = "v${v}"
-}
 if ($Args.Length -eq 1) {
-  $Version = $Args.Get(0)
+  $Version = $Args[0]
+} elseif ($v) {
+  $Version = "v${v}"
 }
 
 $DenoInstall = $env:DENO_INSTALL
 $BinDir = if ($DenoInstall) {
   "${DenoInstall}\bin"
+} elseif (Test-Path variable:\denoGlobalInstall) {
+  "${Env:ProgramFiles}\deno\bin"
 } else {
   "${Home}\.deno\bin"
 }
@@ -38,10 +39,15 @@ tar.exe xf $DenoZip -C $BinDir
 
 Remove-Item $DenoZip
 
-$User = [System.EnvironmentVariableTarget]::User
-$Path = [System.Environment]::GetEnvironmentVariable('Path', $User)
+$EnvTarget = if (Test-Path variable:\denoGlobalInstall) {
+  [System.EnvironmentVariableTarget]::Machine
+} else {
+  [System.EnvironmentVariableTarget]::User
+}
+
+$Path = [System.Environment]::GetEnvironmentVariable('Path', $EnvTarget)
 if (!(";${Path};".ToLower() -like "*;${BinDir};*".ToLower())) {
-  [System.Environment]::SetEnvironmentVariable('Path', "${Path};${BinDir}", $User)
+  [System.Environment]::SetEnvironmentVariable('Path', "${Path};${BinDir}", $EnvTarget)
   $Env:Path += ";${BinDir}"
 }