Dynamically generate command-line command, then invoke using powershell

Two ways to do that:

1. Separate the exe from the arguments

   Do all your dynamic stuff for the arguments, but call the exe as normal with the variable holding the arguments afterward:

   $exe="notepad"
   $argument=""D:\spaced path\HelloWorld.txt""
   &$exe $argument
   
   #or
   notepad $argument
   

   If you have more than one argument, you should make it an array if it will be separate from the exe part of the call:

   $exe="notepad"
   $arguments=""D:\spaced path\HelloWorld.txt"",'--switch1','--switch2'
   &$exe $arguments
   

2. Use Invoke-Expression

   If everything must be in a string, you can invoke the string as if it were a normal expression. Invoke-Expression also has the alias of iex.

   $exp = 'notepad "D:\spaced path\HelloWorld.txt"'
   Invoke-Expression $exp
   

In either case, the contents of the arguments and of the exe should be quoted and formatted appropriately as if it were being written straight on the commandline.