$[      The index of the first element in an array,  and  of
             the  first  character in a substring.  Default is 0,
             but you could set it to 1 to make perl  behave  more
             like  awk  (or  Fortran)  when subscripting and when
             evaluating  the  index()  and  substr()   functions.
             (Mnemonic: [ begins subscripts.)