stty

NAME

stty - set the options for a terminal device interface

SYNOPSIS

stty [-a | -e | -g] [-f file] [operands]

The stty(1) utility sets or reports on terminal characteristics for the device that is its standard input. If no options or operands are specified, it reports the settings of a subset of characteristics and additional ones if they differ from their default values. Otherwise, it modifies the terminal state according to the specified arguments (if it is able). Some combinations of arguments are mutually exclusive on some terminal types. Interix uses a terminal type of interix to describe the console.

The following options are available:

-a: Display all the current settings for the terminal to standard output.
-e: Display all the current settings for the terminal to standard output in the traditional Berkeley Software Distribution (BSD) "all" and "everything" formats.
-f: Open and use the terminal named by file rather than using standard input. The file is opened using the O_NONBLOCK flag of open(3), 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 can be used as an argument to a subsequent invocation of stty(1) to restore the current terminal state.

The following arguments are available to set the terminal characteristics:

Control modes: These flags affect hardware characteristics associated with the terminal
Input modes: These flags affect the characters recognized on input.
Output modes: These flags affect the characters recognized on output.
Control characters: These flags define the control characters recognized by the terminal.
Combination modes: These flags represent useful combinations of other flags.
Compatibility modes: These flags exist for compatibility with older versions of stty(1).

Control modes

Control mode flags affect hardware characteristics associated with the terminal. This corresponds to the c_cflag in the termios 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 the number given, if possible. If the baud rate is set to zero, modem control is no longer asserted.
ispeed number: Set terminal input baud rate to the number given, 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 the number given, 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, if possible.
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.

Input modes

This corresponds to the c_iflag in the termios 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 character 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 512) characters 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 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.
oxtabs (-oxtabs): Expand (do not expand) tabs to spaces on output.

Local modes

Local mode flags (lflags), or "line-discipline flags," affect various characteristics of terminal processing and correspond to the c_lflag of the termios structure.

isig (-isig): Enable (disable) the checking of characters against the special 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 current line from the display, if possible.
echonl (-echonl): Echo (do not echo) NL , even if echo is disabled.
echoctl (-echoctl): If echoctl(1) is set, echo control characters as ^X. Otherwise, control characters echo as themselves.
echoprt (-echoprt): For printing terminals. If set, echo erased characters backwards 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 output. The default behavior is -tostop.
altwerase (-altwerase): Use (do not use) an alternate word-erase algorithm when processing WERASE characters. This alternate algorithm considers sequences of alphanumeric/underscores as words. It also skips the first preceding character in its classification (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 Detect. 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 operation becomes pending or more input arrives.

Control characters

control-character string: Set control-character to string. If string is a single character, the control character is set to that character. If string is the two-character sequence "^-" or the string "undef", the control character is disabled (that is, it is set to {_POSIX_VDISABLE}. Setting the control character also sets the corresponding element of the termios c_cc array.
belltime number: After a bell sounds at the keyboard, any subsequent bells delivered in the next number tenths of a second are ignored. This has no effect on other characters.
min number
time number: Set the value of min or time to number. MIN and TIME are used in non-canonical mode input processing

The recognized control characters are listed in the following table:

Control character	Subscript	Description	Default
belltime	VBELTIME	VBELTIME value	3
dsusp	VDSUSP	DSUSP	No character
eof	VEOF	EOF	^D
eol	VEOL	EOL	No character
eol2	VEOL2	EOL2	No character
erase	VERASE	ERASE	^H
intr	VINTR	INTR	^C
kill	VKILL	KILL	^U
lnext	VLNEXT	LNEXT	^V
min	VMIN	MIN value	1
quit	VQUIT	QUIT	^\
reprint	VREPRINT	REPRINT	^R
start	VSTART	START	^Q
status	VSTATUS	STATUS	No character
stop	VSTOP	STOP	^S
susp	VSUSP	SUSP	^Z
time	VTIME	TIME value	0
werase	VWERASE	WERASE	^W

Combination modes

saved settings

Set the current terminal characteristics to the saved settings 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 terminal use.

tty

Set the line discipline to the standard terminal line discipline 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 identifier (ID), the event the process is waiting 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. On an Interix console window, this will resize the terminal window to have number columns, unless the new size is larger than the physical screen.

cols number

An alias for columns.

rows number

The terminal size is recorded as having number rows. On an Interix console window, this will resize the terminal window to have number rows, unless the new size is larger than the physical screen.

dec

Set modes suitable for users of Digital Equipment Corporation systems ( RASE, 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 processing 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 determine which flags were set prior to setting raw. This means that unsetting raw might not restore all the setting that were previously in effect. To set the terminal into a raw state and then accurately restore it, the following shell code is recommended:

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

size

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

Compatibility modes

These modes remain for compatibility with the previous version of the stty(1) command.

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 tabs.

brk (-value)

Same as the control character eol.

flush (-value)

Same as the control character discard.

rprnt (-value)

Same as the control character reprint.

DIAGNOSTICS

The stty(1) utility exits with a value of 0 if successful, and >0 if an error occurs.