`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 changes the terminal state to reflect those settings.

Terminal settings fall into two major categories:

edit mode: The user can edit the input data. It's made available to programs only when a CR is pressed. Output data is normally presented in a human-readable format.
raw mode: All data flows to and from the terminal with little extra processing.

If you're at a shell prompt, your terminal is probably in the default system edit mode. A full-screen 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 displays only the defined control characters. If -a or -g is specified, then stty displays 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 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 tables below list the operands supported by stty. In these tables, the following conventions are used:

number

A decimal integer number (e.g. 9600).

name

A string of characters (e.g. vt100).

value

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

Some options can start with either + or -:

+: Turn the option on.
-: Turn the option off.

If you don't specify + or -, + 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	Input and output baud rates
`ispeed=`number	Input baud rate
`ospeed=`number	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
{+\|-}`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
`rows=`value[,value]	The number of rows and (optionally) columns of the terminal

Input processing parameters

Parameter	Defines
{+\|-}`ignbrk`	Ignore received hardware breaks
{+\|-}`brkint`	Generate `SIGINT` upon break
{+\|-}`ignpar`	Ignore parity errors
[-]`imaxbel`	Beep and don't flush a full input buffer on a character
{+\|-}`parmrk`	Mark parity errors
{+\|-}`inpck`	Enable software parity checking
{+\|-}`istrip`	Strip 7th bit from received characters
{+\|-}`inlcr`	Map `NL` into `CR` on input
{+\|-}`onlcr`	Map `NL` into `CR` on output
{+\|-}`igncr`	Ignore received `CR`
{+\|-}`icrnl`	Map `CR` into `NL` 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
{+\|-}`echoctl`	Echo control characters in hat notation (e.g `^c`)
{+\|-}`echoe`	Erase character erases displayed character
{+\|-}`echok`	Echo a newline after a kill character
{+\|-}`echoke`	Kill character erases displayed line
{+\|-}`echonl`	Echo `NL`, even if `ECHO` is off
{+\|-}`noflsh`	Don't flush `I/O` after `INTR`, `QUIT`, or `SUSP`
`min=`number	Minimum characters required to satisfy raw input
`time=`number	Timeout value for raw input
{+\|-}`tostop`	Send SIGTTOU for background output.
`+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
`+flush`	Flush all pending input and output
`+raw`	Reset parameters to system default raw mode

Output processing parameters

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

Special control characters

Parameter	Defines
`discard=`value	Discard character
`dsusp=`value	Character for sending a terminal stop signal once input is flushed
`eof=`value	End-of-file character
`eol=`value	End-of-line character
`eol2=`value	Alternative end-of-line character
`erase=`value	Delete previous character
`fwd=`value	Forwarding or framing character; if this character is set, then readcond() returns when either the read length is reached or the FWD character is found in the data stream. For more information, see the entry for readcond() in the QNX Neutrino Library Reference.
`intr=`value	Generate `SIGINT` character
`kill=`value	Delete entire line character
`lnext=`value	Character for entering the next character quoted
`quit=`value	Generate `SIGQUIT` character
`reprint=`value	Character for redrawing the current line
`susp=`value	Generate `SIGTSTP` character
`swtch=`value	Character for switching to a different shell layer
`stop=`value	Stop output
`start=`value	Resume output
`+ek`	Resets `ERASE` and `KILL` to system defaults
`werase=`value	Character for erasing the last word typed

Extended line-editing character sequences

QNX Neutrino supports multicharacter 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 are 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 are 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

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

Restore settings from a shell variable:

stty $saveterm

Exit status:

0: Success.
>0: An error occurred.

Caveats:

The stty utility quietly accepts all of the documented options, but some of the current managers might not support them.