hello | hello
hello${hi}bye | hellobye
ENV hi=hi
hello${hi}bye | hellohibye
ENV space=abc  def
hello${space}bye | helloabc,defbye
hello"${space}"bye | helloabc  defbye
hello "${space}"bye | hello,abc  defbye
ENV leading=  ab c
hello${leading}def | hello,ab,cdef
hello"${leading}" def | hello  ab c,def
hello"${leading}" | hello  ab c
hello${leading} | hello,ab,c
# next line MUST have 3 trailing spaces, don't erase them!
ENV trailing=ab c   
hello${trailing} | helloab,c
hello${trailing}d | helloab,c,d
hello"${trailing}"d | helloab c   d
# next line MUST have 3 trailing spaces, don't erase them!
hel"lo${trailing}" | helloab c   
hello" there  " | hello there  
hello there     | hello,there
hello\ there | hello there
hello" there | error
hello\" there | hello",there
hello"\\there" | hello\there
hello"\there" | hello\there
hello'\\there' | hello\\there
hello'\there' | hello\there
hello'$there' | hello$there
