stty - set the options for a terminal device interface
stty [-a | -e | -g] [-f file] [operands]
The stty 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
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 options are as follows:
-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(2), 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 subsequent
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
characteristics:
Control modes [Toc] [Back]
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.
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 (disable) RTS/CTS flow control.
Input modes [Toc] [Back]
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.
iuclc (-iuclc)
Translate (do not translate) upper case to lower
case 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 255) 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 [Toc] [Back]
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.
ocrnl (-ocrnl)
Translate (do not translate) carriage return to
newline on
output.
onocr (-onocr)
Carriage return is output (is not output) at
column 0.
onlret (-onlret)
Newline performs (does not perform) carriage return on output.
olcuc (-olcuc)
Translate (do not translate) lower case to upper
case on output.
oxtabs (-oxtabs)
Expand (do not expand) tabs to spaces on output.
onoeot (-onoeot)
Discard (do not discard) EOFs on output.
Local modes [Toc] [Back]
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 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 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.
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 noncanonical
to canonical mode and will be re-input
when a read
becomes pending or more input arrives.
xcase (-xcase)
Upper and lower case is (is not) handled canonically on input
and output with iuclc and olcuc.
Control characters [Toc] [Back]
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
(i.e., set to
{_POSIX_VDISABLE}).
Recognized control-characters:
controlcharacter
Subscript Description
_________ _________ _______________
eof VEOF EOF character
eol VEOL EOL character
eol2 VEOL2 EOL2 character
erase VERASE ERASE character
werase VWERASE WERASE character
intr VINTR INTR character
kill VKILL KILL character
quit VQUIT QUIT character
susp VSUSP SUSP character
start VSTART START character
stop VSTOP STOP character
dsusp VDSUSP DSUSP character
lnext VLNEXT LNEXT character
reprint VREPRINT REPRINT character
status VSTATUS STATUS 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 [Toc] [Back]
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 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.
cols number
This is 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 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 intuit
what flags were set prior to setting raw. This
means that
unsetting raw may not put back 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 [Toc] [Back]
These modes remain for compatibility with the previous version of the
stty 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.
lcase (-lcase)
Same as iuclc, olcuc and xcase.
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 [Toc] [Back]
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.
The stty utility exits 0 on success or >0 if an error occurred.
termios(4)
The stty utility is expected to be IEEE Std 1003.2
(``POSIX.2'') compatible.
The flags -e and -f are extensions to the standard, as
are the
operands mentioned in the control operations section.
A stty command appeared in Version 3 AT&T UNIX.
OpenBSD 3.6 June 1, 1994
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