This script writes the path of its folder to user PATH environment (HKEY_CURRENT_USER\Environment - Path). First it checks, if the path exists, and if not, then gives the option to write it.

write_this_folder_to_user_path_env.au3

#cs
	write_this_folder_to_user_path_env.au3 | version 1.0 | written in AutoIt 3
	Description: This script writes the path of its folder to user PATH environment
	             (HKEY_CURRENT_USER\Environment - Path). First it checks, if the path exists,
							 and if not, then gives the option to write it.
	Author: Tibor Repček
	Web: https://gist.github.com/tiborepcek/be334bae9a1851796df37626b8c2c57b
#ce

$currentUserPaths = RegRead("HKEY_CURRENT_USER\Environment", "Path")
$thisFolderDirectory = @ScriptDir

If StringInStr($currentUserPaths, $thisFolderDirectory) = 0 Then ;path not in user path environment
	$question = MsgBox(4, "Question", $thisFolderDirectory & @CRLF & @CRLF & "This path does not exist in user PATH environment. Do you want to write it to the user PATH environment?")
	If $question = 6 Then ;YES button pressed
		RegWrite("HKEY_CURRENT_USER\Environment", "Path", "REG_EXPAND_SZ", ";" & $currentUserPaths & $thisFolderDirectory & ";")
	Else ;NO button pressed
		Exit
	EndIf
Else ;path already exists in user path environment
	MsgBox(64, "Exiting", $thisFolderDirectory & @CRLF & @CRLF & "This path already exists in user PATH environment. This script ends now without writing new path to the user PATH environment.")
EndIf