Manual Pages for UNIX Operating System command usage for man strchg

User Commands                                           strchg(1)



NAME
     strchg, strconf - change or query stream configuration

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


     strchg -p [-a | -u module]


     strchg -f filename


     strconf [-m | -t 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 can
     alter the configuration of that stream.


     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.

OPTIONS
     The following options apply to strchg and, -h,  -f,  and  -p
     are mutually exclusive.

     -a

         Pop all the modules above the  topmost  driver  off  the
         stream. This option requires the -p option.


     -f filename

         Specify a filename  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. strchg determines the current configura-
         tion of the  stream  and  pop  and  push  the  necessary
         modules  in  order to end up with the desired configura-
         tion.



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User Commands                                           strchg(1)



     -h module1 [,module2...]

          Mnemonic for push, 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.


     -p

         Mnemonic for pop, pops modules off the stream. With  the
         -p option alone, strchg pops the topmost module from the
         stream.


     -u module

         All modules above, but not including module  are  popped
         off the stream. This option requires the -p option.



     The following options apply to strconf and, -m  and  -t  are
     mutually exclusive.

     -m module     Determine 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.


     -t module     Print only the topmost module (if one exists).
                   The -t and -m options are mutually exclusive.


EXAMPLES
     Example 1 Using the strchg Command


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


       example% strchg -h ldterm




     The following command  pops  the  topmost  module  from  the
     stream  associated  with  /dev/term/24. The user must be the



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User Commands                                           strchg(1)



     owner of this device or the super user.


       example% strchg -p < /dev/term/24




     If the file fileconf contains the following:


       ttcompat
       ldterm
       ptem



     then the command


       example% strchg -f fileconf




     configures the user's standard  input  stream  so  that  the
     module  ptem  is  pushed over the driver, followed by ldterm
     and ttcompat 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 zs driver, it  would  produce
     the following output:


       ldterm
       zs




     The following command asks if ldterm is on the stream:


       example% strconf -m ldterm








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User Commands                                           strchg(1)



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


       yes



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    | ATTRIBUTE TYPE                ATTRIBUTE VALUE             |
    | Availability                  SUNWcsu                     |
    |___________________________________________________________|


SEE ALSO
     attributes(5), streamio(7I)

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
     filename 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 condi-
     tions,  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 fails. If the user does not
     have read permissions on the stream and  is  not  the  super
     user, the strconf command fails.


     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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