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 the super-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, etc.

         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 -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.



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   strchg(1)                                                         strchg(1)


   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 the super-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

   SEE ALSO
         streamio(7) in the Programmer's Guide: STREAMS.

   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.



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   strchg(1)                                                         strchg(1)


         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.

   NOTES
         If the user is neither the owner of the stream nor the super-user,
         the strchg command will fail.  If the user does not have read
         permissions on the stream and is not the super-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 ttys, if the line
         discipline module is not pushed in the correct place, one could have
         a terminal that does not respond to any commands.




































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