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STTY(1)			  BSD General Commands Manual		       STTY(1)

NAME
     stty -- set options for a terminal	device interface

SYNOPSIS
     stty [-a |	-e | -g] [-f file] [operand ...]

DESCRIPTION
     The stty utility sets or reports on terminal characteristics for the de-
     vice that is its standard input.  If no options or	operands are speci-
     fied, it reports the settings of a	subset of characteristics as well as
     additional	ones if	they differ from their default values.	Otherwise it
     modifies the terminal state according to the specified arguments.	Some
     combinations of arguments are mutually exclusive on some terminal types.

     The following options are available:

     -a		Display	all the	current	settings for the terminal to standard
		output as per IEEE Std 1003.2 ("POSIX.2").

     -e		Display	all the	current	settings for the terminal to standard
		output in the traditional BSD "all" and	"everything" formats.

     -f	file	Open and use the terminal named	by file	rather than using
		standard input.	 The file is opened using the O_NONBLOCK flag
		of open(), making it possible to set or	display	settings on a
		terminal that might otherwise block on the open.

     -g		Display	all the	current	settings for the terminal to standard
		output in a form that may be used as an	argument to a subse-
		quent invocation of stty to restore the	current	terminal state
		as per IEEE Std	1003.2 ("POSIX.2").

     The following arguments are available to set the terminal characteris-
     tics:

   Control Modes
     Control mode flags	affect hardware	characteristics	associated with	the
     terminal.	This corresponds to the	c_cflag	of the termios(4) structure.

     parenb (-parenb)
		 Enable	(disable) parity generation and	detection.

     parodd (-parodd)
		 Select	odd (even) parity.

     cs5 cs6 cs7 cs8
		 Select	character size,	if possible.

     number	 Set terminal baud rate	to number, if possible.	 If the	baud
		 rate is set to	zero, modem control is no longer asserted.

     ispeed number
		 Set terminal input baud rate to number, if possible.  If the
		 input baud rate is set	to zero, the input baud	rate is	set to
		 the value of the output baud rate.

     ospeed number
		 Set terminal output baud rate to number, if possible.	If the
		 output	baud rate is set to zero, modem	control	is no longer
		 asserted.

     speed number
		 This sets both	ispeed and ospeed to number.

     hupcl (-hupcl)
		 Stop asserting	modem control (do not stop asserting modem
		 control) on last close.

     hup (-hup)	 Same as hupcl (-hupcl).

     cstopb (-cstopb)
		 Use two (one) stop bits per character.

     cread (-cread)
		 Enable	(disable) the receiver.

     clocal (-clocal)
		 Assume	a line without (with) modem control.

     crtscts (-crtscts)
		 Enable	RTS/CTS	flow control.

     cdtrcts (-cdtrcts)
		 Enable	DTR/CTS	flow control (if supported).

   Input Modes
     This corresponds to the c_iflag of	the termios(4) structure.

     ignbrk (-ignbrk)
		 Ignore	(do not	ignore)	break on input.

     brkint (-brkint)
		 Signal	(do not	signal)	INTR on	break.

     ignpar (-ignpar)
		 Ignore	(do not	ignore)	parity errors.

     parmrk (-parmrk)
		 Mark (do not mark) parity errors.

     inpck (-inpck)
		 Enable	(disable) input	parity checking.

     istrip (-istrip)
		 Strip (do not strip) input characters to seven	bits.

     inlcr (-inlcr)
		 Map (do not map) NL to	CR on input.

     igncr (-igncr)
		 Ignore	(do not	ignore)	CR on input.

     icrnl (-icrnl)
		 Map (do not map) CR to	NL on input.

     ixon (-ixon)
		 Enable	(disable) START/STOP output control.  Output from the
		 system	is stopped when	the system receives STOP and started
		 when the system receives START, or if ixany is	set, any char-
		 acter restarts	output.

     ixoff (-ixoff)
		 Request that the system send (not send) START/STOP characters
		 when the input	queue is nearly	empty/full.

     ixany (-ixany)
		 Allow any character (allow only START)	to restart output.

     imaxbel (-imaxbel)
		 The system imposes a limit of MAX_INPUT (currently 255) char-
		 acters	in the input queue.  If	imaxbel	is set and the input
		 queue limit has been reached, subsequent input	causes the
		 system	to send	an ASCII BEL character to the output queue
		 (the terminal beeps at	you).  Otherwise, if imaxbel is	unset
		 and the input queue is	full, the next input character causes
		 the entire input and output queues to be discarded.

   Output Modes
     This corresponds to the c_oflag of	the termios(4) structure.

     opost (-opost)
		 Post-process output (do not post-process output; ignore all
		 other output modes).

     onlcr (-onlcr)
		 Map (do not map) NL to	CR-NL on output.

     ocrnl (-ocrnl)
		 Map (do not map) CR to	NL on output.

     oxtabs (-oxtabs)
		 Expand	(do not	expand)	tabs to	spaces on output.

     onocr (-onocr)
		 Do not	(do) output CRs	at column zero.

     onlret (-onlret)
		 On the	terminal NL performs (does not perform)	the CR func-
		 tion.

   Local Modes
     Local mode	flags (lflags) affect various and sundry characteristics of
     terminal processing.  Historically	the term "local" pertained to new job
     control features implemented by Jim Kulp on a PDP-11/70 at	IIASA.	Later
     the driver	ran on the first VAX at	Evans Hall, UC Berkeley, where the job
     control details were greatly modified but the structure definitions and
     names remained essentially	unchanged.  The	second interpretation of the
     `l' in lflag is "line discipline flag", which corresponds to the c_lflag
     of	the termios(4) structure.

     isig (-isig)
		 Enable	(disable) the checking of characters against the spe-
		 cial control characters INTR, QUIT, and SUSP.

     icanon (-icanon)
		 Enable	(disable) canonical input (ERASE and KILL processing).

     iexten (-iexten)
		 Enable	(disable) any implementation defined special control
		 characters not	currently controlled by	icanon,	isig, or ixon.

     echo (-echo)
		 Echo back (do not echo	back) every character typed.

     echoe (-echoe)
		 The ERASE character shall (shall not) visually	erase the last
		 character in the current line from the	display, if possible.

     echok (-echok)
		 Echo (do not echo) NL after KILL character.

     echoke (-echoke)
		 The KILL character shall (shall not) visually erase the cur-
		 rent line from	the display, if	possible.

     echonl (-echonl)
		 Echo (do not echo) NL,	even if	echo is	disabled.

     echoctl (-echoctl)
		 If echoctl is set, echo control characters as ^X.  Otherwise
		 control characters echo as themselves.

     echoprt (-echoprt)
		 For printing terminals.  If set, echo erased characters back-
		 wards within "\" and "/".  Otherwise, disable this feature.

     noflsh (-noflsh)
		 Disable (enable) flush	after INTR, QUIT, SUSP.

     tostop (-tostop)
		 Send (do not send) SIGTTOU for	background output.  This
		 causes	background jobs	to stop	if they	attempt	terminal out-
		 put.

     altwerase (-altwerase)
		 Use (do not use) an alternative word erase algorithm when
		 processing WERASE characters.	This alternative algorithm
		 considers sequences of	alphanumeric/underscores as words.  It
		 also skips the	first preceding	character in its classifica-
		 tion (as a convenience	since the one preceding	character
		 could have been erased	with simply an ERASE character).

     mdmbuf (-mdmbuf)
		 If set, flow control output based on condition	of Carrier De-
		 tect.	Otherwise writes return	an error if Carrier Detect is
		 low (and Carrier is not being ignored with the	CLOCAL flag).

     flusho (-flusho)
		 Indicates output is (is not) being discarded.

     pendin (-pendin)
		 Indicates input is (is	not) pending after a switch from non-
		 canonical to canonical	mode and will be re-input when a read
		 becomes pending or more input arrives.

   Control Characters
     control-character string
		 Set control-character to string string.  If the string	is a
		 single	character, then	the control character is set to	that
		 character.  If	the string is the two character	sequence "^-"
		 or the	string "undef",	then the control character is disabled
		 (i.e.,	set to {_POSIX_VDISABLE}).

		 Recognized control characters:

		       control-
		       character    Subscript	 Description
		       _________    _________	 _______________
		       eof	    VEOF	 EOF character
		       eol	    VEOL	 EOL character
		       eol2	    VEOL2	 EOL2 character
		       erase	    VERASE	 ERASE character
		       werase	    VWERASE	 WERASE	character
		       kill	    VKILL	 KILL character
		       reprint	    VREPRINT	 REPRINT character
		       intr	    VINTR	 INTR character
		       quit	    VQUIT	 QUIT character
		       susp	    VSUSP	 SUSP character
		       dsusp	    VDSUSP	 DSUSP character
		       start	    VSTART	 START character
		       stop	    VSTOP	 STOP character
		       lnext	    VLNEXT	 LNEXT character
		       status	    VSTATUS	 STATUS	character
		       discard	    VDISCARD	 DISCARD character

     min number

     time number
		 Set the value of min or time to number.  MIN and TIME are
		 used in Non-Canonical mode input processing (-icanon).

   Combination Modes
     saved settings
		 Set the current terminal characteristics to the saved set-
		 tings produced	by the -g option.

     evenp or parity
		 Enable	parenb and cs7;	disable	parodd.

     oddp	 Enable	parenb,	cs7, and parodd.

     -parity, -evenp, -oddp
		 Disable parenb, and set cs8.

     nl	(-nl)	 Enable	(disable) icrnl.  In addition -nl unsets inlcr and
		 igncr.

     ek		 Reset ERASE and KILL characters back to system	defaults.

     sane	 Resets	all modes to reasonable	values for interactive termi-
		 nal use.

     insane	 Sets all modes	to random values, which	are very likely	(but
		 not guaranteed) to be unreasonable for	interactive terminal
		 use.

     tty	 Set the line discipline to the	standard terminal line disci-
		 pline TTYDISC.

     crt (-crt)	 Set (disable) all modes suitable for a	CRT display device.

     kerninfo (-kerninfo)
		 Enable	(disable) the system generated status line associated
		 with processing a STATUS character (usually set to ^T).  The
		 status	line consists of the system load average, the current
		 command name, its process ID, the event the process is	wait-
		 ing on	(or the	status of the process),	the user and system
		 times,	percent	CPU, and current memory	usage.

     columns number
		 The terminal size is recorded as having number	columns.

     cols number
		 An alias for columns.

     rows number
		 The terminal size is recorded as having number	rows.

     dec	 Set modes suitable for	users of Digital Equipment Corporation
		 systems (ERASE, KILL, and INTR	characters are set to ^?, ^U,
		 and ^C; ixany is disabled, and	crt is enabled).

     extproc (-extproc)
		 If set, this flag indicates that some amount of terminal pro-
		 cessing is being performed by either the terminal hardware or
		 by the	remote side connected to a pty.

     raw (-raw)	 If set, change	the modes of the terminal so that no input or
		 output	processing is performed.  If unset, change the modes
		 of the	terminal to some reasonable state that performs	input
		 and output processing.	 Note that since the terminal driver
		 no longer has a single	RAW bit, it is not possible to intuit
		 what flags were set prior to setting raw.  This means that
		 unsetting raw may not put back	all the	setting	that were pre-
		 viously in effect.  To	set the	terminal into a	raw state and
		 then accurately restore it, the following shell code is rec-
		 ommended:

		       save_state=$(stty -g)
		       stty raw
		       ...
		       stty "$save_state"

     size	 The size of the terminal is printed as	two numbers on a sin-
		 gle line, first rows, then columns.

   Compatibility Modes
     These modes remain	for compatibility with the previous version of the
     stty utility.

     all	 Reports all the terminal modes	as with	stty -a	except that
		 the control characters	are printed in a columnar format.

     everything	 Same as all.

     cooked	 Same as sane.

     cbreak	 If set, enables brkint, ixon, imaxbel,	opost, isig, iexten,
		 and -icanon.  If unset, same as sane.

     new	 Same as tty.

     old	 Same as tty.

     newcrt (-newcrt)
		 Same as crt.

     pass8	 The converse of parity.

     tandem (-tandem)
		 Same as ixoff.

     decctlq (-decctlq)
		 The converse of ixany.

     crterase (-crterase)
		 Same as echoe.

     crtbs (-crtbs)
		 Same as echoe.

     crtkill (-crtkill)
		 Same as echoke.

     ctlecho (-ctlecho)
		 Same as echoctl.

     prterase (-prterase)
		 Same as echoprt.

     litout (-litout)
		 The converse of opost.

     tabs (-tabs)
		 The converse of oxtabs.

     brk value	 Same as the control character eol.

     flush value
		 Same as the control character discard.

     rprnt value
		 Same as the control character reprint.

   Control operations
     These operations are not modes, but rather	commands to be performed by
     the tty layer.

     ostart	 Performs a "start output" operation, as normally done by an
		 incoming START	character when ixon is set.

     ostop	 Performs a "stop output" operation, as	normally done by an
		 incoming STOP character when ixon is set.

EXIT STATUS
     The stty utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     termios(4), tty(4)

STANDARDS
     The stty utility is expected to be	IEEE Std 1003.2	("POSIX.2") compati-
     ble.  The -e and -f flags are extensions to the standard, as are the op-
     erands mentioned in the control operations	section.

BSD				 June 16, 2012				   BSD

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | SEE ALSO | STANDARDS

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