Hi,

       I  read  the bash manual and it is a very good one, but I don't
    really understand something in the second node titled definitions.
    May  be  there  is a little inconsequence in it or I misinterpret.
    Shortly, the terms 'word', 'control operator' and  'operator'  are
    not  clear.  A  more  detailed  explanation with some mathematical
    deduction is following :)
    Take a look these original definitions:

    1) control operator
        A word that performs a control function. It is  a  newline  or
    one of the following: LIST
    2) operator
        A control operator or a redirection operator
    3) word
        A token that is not an operator

    I will use some notation to be easier to explain myself:
    co = control operator
    ro = redirection operator
    o  = operator
    w  = word
    t  = token

    Let
    U = Union
    C = Subset
    § = Intersection

    I  know  this  last  two  are  a little stupid sign...  Then 1,2,3
    statements with these symbols looks like:

    1) co C w
    2) o = co U ro
    3) w § o = nil

    Now we may write:

        nil =  w § o  =  w § ( co U ro )  =  ( w § co ) U ( w § ro )

    We know that

        w § co = co

    so we find that

        nil = co U ( w § ro )

    So in the best case, if

        w § ro = nil

    it say something like there is no such thing  control  operator...
    It  is  a  nil  set.  But  it is not a nil set, because it has the
    elements newline and LIST. Put another way, `o' has a subset `co';
    and  `co'  is  a  subset  of  the  `w';  so  it  is  imposible the
    intersection of `w' and `o' is nil, but the third  statement  says
    exactly this.
    There is two option:
    A) It is something wrong with the 1,2,3 definitions
    B) I misinterpret something
    I  am waiting for your answer excitedly, and sorry that my English
    is very poor.



                                                  Yours very truly,
                                                             David.