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strchg(1)							    strchg(1)



NAME

  strchg, strconf - Alters and queries stream configuration

SYNOPSIS

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

  strchg -p  [-a  | -u module]

  strchg -f file

  strconf [-t  | -m module]

  The strchg and strconf commands modify and return information	about the
  configuration	of the Stream associated with the user's standard input.

OPTIONS

  The strchg command has three formats,	which must be specified	separately.
  These	formats	offer the following options:

  -a module
      When used	with -p, removes all of	the STREAMS modules above the topmost
      driver; that is, the command only	affects	the uppermost Stream created
      for a multiplexed	driver,	not any	of the lower Streams. This option
      cannot be	used with -u.

  -f file
      Specifies	a file that contains a list of STREAMS modules to be pushed
      on the standard input Stream for a desired configuration.	The names of
      the modules must occupy separate lines in	the file. The strchg command
      pushes any module	that is	desired	but is not present on the Stream, and
      pops any module that is not desired and is present on the	Stream.

  -h module1[,module2, ... modulen]
      Pushes the STREAMS module	or modules specified by	the module argument
      or arguments on the standard input Stream.  The command pushes the
      STREAMS modules on the Stream in the order that they are specified;
      that is, module1 is pushed first,	module2	is pushed second, and so
      forth.

  -p  Pops STREAMS modules off the standard input Stream. When the -p option
      is specified without any other options, the command removes the topmost
      module (the module immediately below the Stream head) from the Stream.
      The -a and -u options cannot be used simultaneously with the -p option.

  -u module
      When used	with -p, pops all of the modules above the specified module
      off the Stream, leaving that module on it. This option cannot be used
      with -a.


  The strconf command options are the following:

  -t module
      Prints the name of the topmost module on the standard input Stream, if
      this module exists.

  -m module
      Confirms whether or not the specified module module is present on	the
      Stream.

DESCRIPTION

  The strchg command pushes and	pops STREAMS modules on	and off	the user's
  standard input Stream	to achieve a desired configuration. The	strconf	com-
  mand queries the configuration of the	Stream,	then prints the	names of the
  modules and the topmost device driver, or the	name of	the topmost module,
  or the name of a specific module.

  When the -f option is	used, the strchg command first determines the current
  configuration	of the standard	input Stream, then pushes or pops the modules
  named	in the file argument to	fix it.	 The module that is named first	is
  meant	to be the one that is located below the	Stream head, while the module
  named	last is	meant to be at the bottom of the Stream, closest to the	dev-
  ice driver. This is the opposite of the order	in which the strchg command
  pushes and pops modules when it is invoked with the -h option.

  To use the strchg command, you must either be	the owner of the Stream	or
  the superuser.

  Without options, the strconf command prints the names	of all of the
  modules, if any, and the name	of the topmost driver. Names are printed one
  per line, with the driver's name last. When the autopush mechanism is	used
  in a system, the strconf command returns the names of	the modules that were
  automatically	pushed on the standard input Stream at the opening of the
  associated device. If	the Stream configuration has been changed since	the
  device was opened, the command prints	the altered list of module names.

  If the -t option is used, the	strconf	command	prints only the	topmost
  module's name, if any	exists.	When the -m option is used, the	command
  queries the standard input Stream for	the module specified in	the module
  argument. If this module is present on the Stream, it	prints the message
  yes and returns a 0 (zero).  If the module is	not on the Stream, strchg
  prints no and	returns	a nonzero value. The -t	and -m options cannot be used
  simultaneously.

  To use the strconf command, you must either have read	permission or be the
  superuser.

  For both the strchg and strconf commands, note that if modules are pushed
  onto the user's standard input Stream	in the wrong order, that Stream	will
  not function as expected. For	example, in the	case of	terminal lines
  (ttys), the line discipline module must be pushed in the correct place;
  otherwise, the terminal might	not respond correctly to commands.

EXIT STATUS

  The strchg command returns 0 (zero) on success. When the command encounters
  an error, it returns a nonzero status	and prints an error message.  The
  command returns errors for such conditions as	a usage	error, bad module
  name,	failure	of an ioctl system call, and failure to	open the file speci-
  fied by the -f option.

  The strconf command returns 0	(zero) on success and a	nonzero	status for
  errors.  It prints an	error message for any errors. When the -m and -t
  options return successfully, this indicates that the named, or topmost,
  module is present.  The error	conditions that	the command returns a status
  for include a	usage error and	a failure of an	ioctl system call.






EXAMPLES

   1.  To print	out the	names of the modules and driver	present	on the user's
       standard	input Stream, enter:
	    strconf

   2.  To push the fictional line discipline module linedisp onto the user's
       standard	input Stream, enter:
	    strchg -h linedisp

       The ldterm module is pushed below the Stream head in the	user's stan-
       dard input Stream.

   3.  To set up the standard input Stream (JIS) characters, and to do this
       using a previously created file called /$HOME/.mytty.conf that lists
       the modules, enter:
	    strchg -f $HOME/.mytty.conf

       If the list of modules in the /$HOME/.mytty.conf	file is	as follows,
       the fictional lpass module will be pushed first,	followed by the	fic-
       tional linedisp module, followed	by the fictional upass module.


	    upass
	    linedisp
	    lpass



SEE ALSO

  Commands:  autopush(8)

  Interfaces:  streamio(7)