[...discussion of HTTP-EQUIV mode of tagging...]
    In either case the server will open the file process the header lines
    and output the appropriate information on the wire.
As has been pointed out elsewhere, one can't parse an SGML file to obtain the
character set tag without knowing the character set which the tag purports
to identify. To quote from ISO 8879:1986, clause 13.1, which defines
the production [172] "document character set" in the SGML declaration:
  NOTE -- It is recognized that the recipient of a document must be able
  to translate it to his system character set before the document can be
  processed by machine.  There are two basic approaches to communicating
  this information:
  a) If the character set is standard, registered, or otherwise capable of
     being referenced by an identifying name or number, that identifier can
     be communicated to the recipient of the document.  The communication
                                                        ^^^^^^^^^^^^^^^^^
     must necessarily occur outside of the document...
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And the last para. on pg. 452 of the SGML Handbook, referring to the above
says:
  "As the last note implies, the document character set parameter is ignored
  by the SGML parser because the document is already in the document character
  set. The parameter is intended for a human to read in printed form, in
  order to determine how to trarnslate an incoming document to the local
  system character set."
Regards,
Glenn