strchg(1)                                                  strchg(1)


       NAME
             strchg, strconf - change or query stream configuration

       SYNOPSIS
             strchg -h module1[,module2 . . .]
             strchg -p [-a | -u module]
             strchg -f file
             strconf [-t | -m module]

       DESCRIPTION
             These commands are used to alter or query the configuration of
             the stream associated with the user's standard input.  The
             strchg command pushes modules on and/or pops modules off the
             stream.  The strconf command queries the configuration of the
             stream.  Only a privileged user or owner of a STREAMS device
             may alter the configuration of that stream.

             With the -h option, strchg pushes modules onto a stream; it
             takes as arguments the names of one or more pushable streams
             modules.  These modules are pushed in order; that is, module1
             is pushed first, module2 is pushed second, and so on.

             The -p option pops modules off the stream.  With the -p option
             alone, strchg pops the topmost module from the stream.  With
             the -p and -a options, all the modules above the topmost
             driver are popped.  When the -p option is followed by -u
             module, then all modules above but not including module are
             popped off the stream.  The -a and -u options are mutually
             exclusive.

             With the -f option, the user can specify a file that contains
             a list of modules representing the desired configuration of
             the stream.  Each module name must appear on a separate line
             where the first name represents the topmost module and the
             last name represents the module that should be closest to the
             driver.  The strchg command will determine the current
             configuration of the stream and pop and push the necessary
             modules in order to end up with the desired configuration.

             The -h, -f and -p options are mutually exclusive.

             Invoked without any arguments, strconf prints a list of all
             the modules in the stream as well as the topmost driver.  The
             list is printed with one name per line where the first name
             printed is the topmost module on the stream (if one exists)
             and the last item printed is the name of the driver.  With the


                           Copyright 1994 Novell, Inc.               Page 1

      strchg(1)                                                  strchg(1)


            -t option, only the topmost module (if one exists) is printed.
            The -m option determines if the named module is present on a
            stream.  If it is, strconf prints the message yes and returns
            zero.  If not, strconf prints the message no and returns a
            non-zero value.  The -t and -m options are mutually exclusive.

      EXAMPLES
            The following command pushes the module ldterm on the stream
            associated with the user's standard input:
                  strchg -h ldterm

            The following command pops the topmost module from the stream
            associated with /dev/term/24.  The user must be the owner of
            this device or a privileged user.
                  strchg -p < /dev/term/24

            If the file fileconf contains the following:
                  compat
                  ldterm
                  ptem

            then the command
                  strchg -f fileconf

            will configure the user's standard input stream so that the
            module ptem is pushed over the driver, followed by ldterm and
            compat closest to the stream head.

            The strconf command with no arguments lists the modules and
            topmost driver on the stream; for a stream that has only the
            module ldterm pushed above the ports driver, it would produce
            the following output:
                  ldterm
                  ports

            The following command asks if ldterm is on the stream
                  strconf -m ldterm

            and produces the following output while returning an exit
            status of 0:
                  yes

      REFERENCES
            streamio(7)




                          Copyright 1994 Novell, Inc.               Page 2

       strchg(1)                                                  strchg(1)


       DIAGNOSTICS
             strchg returns zero on success.  It prints an error message
             and returns non-zero status for various error conditions,
             including usage error, bad module name, too many modules to
             push, failure of an ioctl on the stream, or failure to open
             file from the -f option.

             strconf returns zero on success (for the -m or -t option,
             ``success'' means the named or topmost module is present).  It
             returns a non-zero status if invoked with the -m or -t option
             and the module is not present.  It prints an error message and
             returns non-zero status for various error conditions,
             including usage error or failure of an ioctl on the stream.

       NOTICES
             If the user is neither the owner of the stream nor a
             privileged user, the strchg command will fail.  If the user
             does not have read permissions on the stream and is not a
             privileged user, the strconf command will fail.

             If modules are pushed in the wrong order, one could end up
             with a stream that does not function as expected.  For
             terminals, if the line discipline module is not pushed in the
             correct place, one could have a terminal that does not respond
             to any commands.























                           Copyright 1994 Novell, Inc.               Page 3