strchg(1M)                                                       strchg(1M)




 NAME    [Toc]    [Back]
      strchg, strconf - change or query stream configuration

 SYNOPSIS    [Toc]    [Back]
      strchg -h module1[, module2]...

      strchg -p [ -a|-u module]

      strchg -f file

      strconf

      strconf -t

      strconf -m module

 DESCRIPTION    [Toc]    [Back]
      The strchg and strconf commands are used to change 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 superuser or owner of a STREAMS device may alter the
      configuration of that stream.

    strchg Options
      The strchg command uses the following options:

      -h module1[,module2] ...
                          strchg pushes modules onto a stream.  The modules
                          are pushable STREAMS modules as defined by
                          module1, module2, and so on.  The modules are
                          pushed in order.  That is, module1 is pushed
                          first, module2 is pushed second, etc.

      -p                  With the -p option alone, strchg pops the topmost
                          module from the stream.

      -a                  With the -p and -a options, all the modules above
                          the topmost driver are popped.

      -u module           With the -p and -u module options, all modules
                          above but not including module are popped off the
                          stream.

      The -a and -u options are mutually exclusive.

      -f file             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



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 strchg(1M)                                                       strchg(1M)




                          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.

    strconf Options
      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 in 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.

      The strconf command uses the following options:

      -t             Only the topmost module (if one exists) is printed.

      -m module      strconf checks if the named module is present on the
                     stream.  If so, 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.

    Notes    [Toc]    [Back]
      If the user is neither the owner of the stream nor the superuser, the
      strchg command will fail.  If the user does not have read permissions
      on the stream and is not the superuser, 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.

 DIAGNOSTICS    [Toc]    [Back]
      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.

 EXAMPLES    [Toc]    [Back]
      The following command pushes the module ldterm on the stream



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 strchg(1M)                                                       strchg(1M)




      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 be superuser.

           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 only has 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

 FILES    [Toc]    [Back]
      /usr/lib/nls/msg/C/strchg.cat                     NLS catalogs
      /usr/lib/nls/msg/C/strconf.cat                    NLS catalogs

 SEE ALSO    [Toc]    [Back]
      streamio(7).


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