`stty`

Set tty attributes (POSIX)

Syntax:

stty [-a|-g] [operands] [< device]

Options:

-a: Display all settings.
-g: Display in "getable" form.

The stty utility sets and/or reports terminal I/O characteristics for the device that is its standard input. If no operands are specified, stty displays the settings. If operands are given, then stty will change the terminal state to reflect those settings.

Terminal settings fall into two major categories: edit mode or raw mode. In edit mode, input data can be edited by the user, and is made available to programs only when an Enter is pressed. Output data will normally be presented in a human-readable format. In raw mode, all data flows to and from the terminal with little extra processing. If you're at a shell prompt, your terminal will probably be in the default system edit mode. A fullscreen program such as an editor, on the other hand, typically puts the terminal into raw mode.

Normally, stty displays only significant settings relative to the system default settings for edit or raw, and will display only the defined control characters. If -a or -g are specified, then stty will display all the settings.

The stty utility manages a very large number of potential terminal attributes and control characters. Most of these parameters are very device-specific and will seldom need to be changed by the user. Programs often change these terminal attributes in the course of their operation, and upon occasion (such as abnormal termination) may leave the terminal settings in an unknown state. The stty +edit option is a convenient method of restoring a terminal to a usable state.

Supported operands

The complete list of operands supported by stty are provided in the following tables. In these tables, the following conventions are used:

number

represents a decimal integer number (e.g. 9600).

name

represents a string of characters (e.g. vt100).

value

can be a single character (e.g. ~) or a 2-digit hexadecimal number (e.g. 1B) or one of the following character pairs:

Char pair	Hex
`^-`	00 (undefined)
`^A` to `^Z`	01 to 1A
`^[`	1B
`^\`	1C
`^]`	1D
`^^`	1E
`^_`	1F
`^?`	7F

An option that starts with {+|-} can start with either of these characters:

+: (turn the option on)
-: (turn the option off)

If neither + nor - is specified, + is assumed.

Also note that the = character is optional in operands of the form keyword=value.

The following descriptions give the action taken when the option is on.

Line control parameters

Parameter	Defines
`baud=`number	define input and output baud rates
`ispeed=`number	define input baud rate
`ospeed=`number	define output baud rate
`par=none`	no parity (same as `-parenb`)
`par=odd`	odd parity (same as `+parenb`, `+parodd`, `-parstk`)
`par=even`	even parity (same as `+parenb`, `-parodd`, `-parstk`)
`par=mark`	mark parity (same as `+parenb`,`+parodd`, `+parstk`)
`par=space`	space parity (same as `+parenb`, `-parodd`, `+parstk`)
`bits=5`	5-bit characters
`bits=6`	6-bit characters
`bits=7`	7-bit characters
`bits=8`	8-bit characters
`stopb=2`	2-stop bits
`stopb=1`	1-stop bits
{+\|-}`parenb`	enable parity
`+parodd`	odd parity
`-parodd`	even parity
{+\|-}`parstk`	stick parity
`+cs5`	same as `bits=5`
`+cs6`	same as `bits=6`
`+cs7`	same as `bits=7`
`+cs8`	same as `bits=8`
`+cstopb`	same as `stopb=2`
`-cstopb`	same as `stopb=1`
number	same as `baud=`number
`+evenp`	same as `par=even`, `bits=7`
`-evenp`	same as `par=none`, `bits=8`
`+parity`	same as `par=even`, `bits=7`
`-parity`	same as `par=none`, `bits=8`
`+oddp`	same as `par=odd`, `bits=7`
`-oddp`	same as `par=none`, `bits=8`
{+\|-}`hupcl`	hangup on last close
{+\|-}`hup`	same as `hupcl`
{+\|-}`cread`	enable receiver
{+\|-}`clocal`	assume no modem control
{+\|-}`ihflow`	enable hardware input flow control
{+\|-}`ohflow`	enable hardware output flow control
{+\|-}`isflow`	enable software input flow control
{+\|-}`osflow`	enable software output flow control
{+\|-}`lkhflow`	lock hardware flow control (`ihflow`/`ohflow`)
{+\|-}`lksflow`	lock software flow control (`isflow`/`osflow`)
{+\|-}`ihpaged`	input is paged by hardware flow control
{+\|-}`ohpaged`	output is paged by hardware flow control
{+\|-}`ispaged`	input is paged by software flow control
{+\|-}`ospaged`	output is paged by software flow control

Input processing parameters

Parameter	Defines
{+\|-}`ignbrk`	ignore received hardware breaks
{+\|-}`brkint`	generate SIGINT upon break
{+\|-}`ignpar`	ignore parity errors
{+\|-}`parmrk`	mark parity errors
{+\|-}`inpck`	enable software parity checking
{+\|-}`istrip`	strip 8th bit from received characters
{+\|-}`inlcr`	map `newline` into `carriage-return` on input
{+\|-}`igncr`	ignore received `carriage-return`
{+\|-}`icrnl`	map `carriage-return` into `newline` on input
{+\|-}`ixon`	same as osflow
{+\|-}`ixoff`	same as isflow
{+\|-}`isig`	generate signals upon receipt of special characters
{+\|-}`icanon`	enable input line editing
{+\|-}`iexten`	enable "extra" special characters
{+\|-}`echo`	echo received characters
{+\|-}`echoe`	erase character will erase displayed character
{+\|-}`echok`	kill character will erase displayed line
{+\|-}`echonl`	echo `newline`, even if `ECHO` is off
{+\|-}`noflsh`	don't flush I/O after `INTR`, `QUIT`, or `SUSP`
`+flush`	flush input and output data immediately
`min=`number	minimum characters required to satisfy raw input
`time=`number	timeout value for raw input
`+nl`	same as `+icrnl`
`-nl`	same as `-icrnl`, `-inlcr`, `-igncr`
`+sane`	reset all parameters to sane values based on current mode (edit/raw)
`+fix`	same as `+sane`
`+edit`	reset parameters to system default edit mode
`+raw`	reset parameters to system default raw mode

Output processing parameters

Parameter	Defines
{+\|-}`opost`	post-process output data

Special control characters

Parameter	Defines
`eof=`value	end-of-file character
`eol=`value	end-of-line character
`erase=`value	delete previous character
`kill=`value	delete entire line character
`intr=`value	generate SIGINT character
`quit=`value	generate SIGQUIT character
`susp=`value	generate SIGTSTP character
`stop=`value	stop output
`start=`value	resume output
`+ek`	resets `ERASE` and `KILL` to system defaults

Extended line-editing character sequences

QNX supports multi-character sequences to support editing capabilities in addition to the basic "erase" and "kill" functions. All of these sequences are assumed to start with an (up to) 4-character prefix, a single-character action, followed by an (up to) 4-character suffix. Typically, the cursor keys on your terminal will be used for these functions.

Parameter	Meaning
`+load`	set editing keys based on currently defined terminal type
`term=`name	set editing keys for the specified type of terminal
`pr1=`value	first character of prefix
`pr2=`value	second character of prefix
`pr3=`value	third character of prefix
`pr4=`value	fourth character of prefix
`sf1=`value	first character of suffix
`sf2=`value	second character of suffix
`sf3=`value	third character of suffix
`sf4=`value	fourth character of suffix

Action characters

The following are action characters when preceded by prefix (subsequent suffix will be discarded).

Parameter	Meaning
`up=`value	recall previous line
`down=`value	recall next line
`left=`value	move cursor left
`right=`value	move cursor right
`ins=`value	toggle insert mode
`del=`value	delete current character
`rub=`value	delete previous character
`can=`value	delete entire line character
`home=`value	move cursor to beginning of line
`end=`value	move cursor to end of line

Console-specific options

Parameter	Meaning
{+\|-}`numlock`	keyboard is in Num Lock mode
{+\|-}`capslock`	keyboard is in Caps Lock mode
{+\|-}`scrlock`	keyboard is in Scroll Lock mode
{+\|-}`noboot`	disable keyboard reboot
{+\|-}`noswitch`	disable keyboard console switching
{+\|-}`nodebug`	disable keyboard debugger entry
{+\|-}`noresize`	disable keyboard resizing
{+\|-}`nohotkey`	disable keyboard hotkeys
{+\|-}`nocolor`	disable colors on console display
{+\|-}`monocurs`	force cursor to monochrome adapter values
{+\|-}`extmode`	put keyboard into extended mode
{+\|-}`scanmode`	put keyboard into scancode mode
`rows=`rows[`,`cols]	set console size
`font=`value	set console font

Serial port-specific options

Parameter	Meaning
{+\|-}`DTR`	turn on data-terminal-ready hardware handshaking line
{+\|-}`RTS`	turn on request-to-send hardware handshaking line
{+\|-}`BRK`	force transmit data line to break condition

The QNX Installation & Configuration manual gives more detailed information concerning the circumstances under which many of these options will be required.

The stty utility usually displays as much information about a device as it can. Unless the -g option is set, the following settings may also be displayed, depending on the type of device:

Serial port information

Parameter	Meaning
{+\|-}`cts`	clear-to-send line is on
{+\|-}`dsr`	data-set-ready line is on
{+\|-}`ri`	ring indicator is on
{+\|-}`cd`	carrier detect is on

Parallel port information

Parameter	Meaning
{+\|-}`ERR`	error condition is set
{+\|-}`ONL`	printer is online
{+\|-}`PE`	paper-empty indicator
{+\|-}`BSY`	printer is busy

Examples:

Display settings of the terminal to which stty is attached:

    stty

Display settings of a specified device:

    stty < /dev/ser1

Change the baud rate of a specified device:

    stty baud=1200 < /dev/ser1

Put terminal into a fixed, sane state:

    stty +sane

Set editing keys to VT100 values:

    stty term=vt100

Get current settings into a shell variable:

    saveterm = "$(stty -g)"

Restore settings from a shell variable:

    stty $saveterm

Exit status:

0: The utility executed successfully.
>0: An error occurred.