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📟 stty: Print or change terminal characteristics

🚀 Quick Reference

Use Case	Command	Description
Show all settings	stty -a	Print all current terminal settings in human‑readable form
Save current settings	stty -g	Output settings in a format that can be reused to restore later
Restore sane defaults	stty sane	Reset the terminal to a known‑good state
Set raw mode	stty raw	Disable all input and output processing; pass everything through
Set cooked mode	stty cooked	Enable line‑by‑line input processing with echo
Change baud rate	stty 9600	Set both input and output speed to 9600 bps
Disable echo	stty -echo	Stop echoing typed characters (useful for password prompts)
Show terminal size	stty size	Print the number of rows and columns the kernel thinks the terminal has

📋 Synopsis

stty [OPTION] [SETTING]...
stty [OPTION]

📖 Description

If given no line settings, stty prints the baud rate, line discipline number (on systems that support it), and line settings that have been changed from the values set by stty sane. By default, mode reading and setting are performed on the tty line connected to standard input, although this can be modified by the --file option.

Many settings can be turned off by preceding them with a -. Such arguments are marked below with “May be negated” in their description. The descriptions themselves refer to the positive case, that is, when not negated (unless stated otherwise).

Some settings are not available on all POSIX systems, since they use extensions. Such arguments are marked below with “Non‑POSIX” in their description. On non‑POSIX systems, those or other settings also may not be available, but it’s not feasible to document all the variations: just try it and see.

stty is installed only on platforms with the POSIX terminal interface, so portable scripts should not rely on its existence on non‑POSIX platforms.

⚙️ Options

-a, --all 🔍 Print all current settings in human‑readable form. This option may not be used in combination with any line settings. -F DEVICE, --file=DEVICE 📁 Set the line opened by the file name specified in DEVICE instead of the tty line connected to standard input. This option is necessary because opening a POSIX tty requires use of the O_NONDELAY flag to prevent a POSIX tty from blocking until the carrier detect line is high if the clocal flag is not set. Hence, it is not always possible to allow the shell to open the device in the traditional manner. -g, --save 💾 Print all current settings in a form that can be used as an argument to another stty command to restore the current settings. This option may not be used in combination with any line settings.

🎛️ Control Settings

parenb Generate parity bit in output and expect parity bit in input. May be negated. parodd Set odd parity (even if negated). May be negated. cmspar Use “stick” (mark/space) parity. If parodd is set, the parity bit is always 1; if parodd is not set, the parity bit is always zero. Non‑POSIX. May be negated. cs5 Set character size to 5 bits. cs6 Set character size to 6 bits. cs7 Set character size to 7 bits. cs8 Set character size to 8 bits. hup, hupcl Send a hangup signal when the last process closes the tty. May be negated. cstopb Use two stop bits per character (one if negated). May be negated. cread Allow input to be received. May be negated. clocal Disable modem control signals. May be negated. crtscts Enable RTS/CTS flow control. Non‑POSIX. May be negated. cdtrdsr Enable DTR/DSR flow control. Non‑POSIX. May be negated.

📥 Input Settings

These settings control operations on data received from the terminal.

ignbrk Ignore break characters. May be negated. brkint Make breaks cause an interrupt signal. May be negated. ignpar Ignore characters with parity errors. May be negated. parmrk Mark parity errors (with a 255‑0‑character sequence). May be negated. inpck Enable input parity checking. May be negated. istrip Clear high (8th) bit of input characters. May be negated. inlcr Translate newline to carriage return. May be negated. igncr Ignore carriage return. May be negated. icrnl Translate carriage return to newline. May be negated. iutf8 Assume input characters are UTF‑8 encoded. May be negated. ixon Enable XON/XOFF flow control (that is, Ctrl‑S/Ctrl‑Q). May be negated. ixoff, tandem Enable sending of stop character when the system input buffer is almost full, and start character when it becomes almost empty again. May be negated. iuclc Translate uppercase characters to lowercase. Non‑POSIX. May be negated. Note ilcuc is not implemented, as one would not be able to issue almost any (lowercase) Unix command, after invoking it. ixany Allow any character to restart output (only the start character if negated). Non‑POSIX. May be negated. imaxbel Enable beeping and not flushing input buffer if a character arrives when the input buffer is full. Non‑POSIX. May be negated.

📤 Output Settings

These settings control operations on data sent to the terminal.

opost Postprocess output. May be negated. olcuc Translate lowercase characters to uppercase. Non‑POSIX. May be negated. (Note ouclc is not currently implemented.) ocrnl Translate carriage return to newline. Non‑POSIX. May be negated. onlcr Translate newline to carriage return‑newline. Non‑POSIX. May be negated. onocr Do not print carriage returns in the first column. Non‑POSIX. May be negated. onlret Newline performs a carriage return. Non‑POSIX. May be negated. ofill Use fill (padding) characters instead of timing for delays. Non‑POSIX. May be negated. ofdel Use ASCII DEL characters for fill instead of ASCII NUL characters. Non‑POSIX. May be negated. nl1, nl0 Newline delay style. Non‑POSIX. cr3, cr2, cr1, cr0 Carriage return delay style. Non‑POSIX. tab3, tab2, tab1, tab0 Horizontal tab delay style. Non‑POSIX. bs1, bs0 Backspace delay style. Non‑POSIX. vt1, vt0 Vertical tab delay style. Non‑POSIX. ff1, ff0 Form feed delay style. Non‑POSIX.

🏠 Local Settings

isig Enable interrupt, quit, and suspend special characters. May be negated. icanon Enable erase, kill, werase, and rprnt special characters. May be negated. iexten Enable non‑POSIX special characters. May be negated. echo Echo input characters. May be negated. echoe, crterase Echo erase characters as backspace‑space‑backspace. May be negated. echok Echo a newline after a kill character. May be negated. echonl Echo newline even if not echoing other characters. May be negated. noflsh Disable flushing after interrupt and quit special characters. May be negated. xcase Enable input and output of uppercase characters by preceding their lowercase equivalents with \, when icanon is set. Non‑POSIX. May be negated. tostop Stop background jobs that try to write to the terminal. Non‑POSIX. May be negated. echoprt, prterase Echo erased characters backward, between \ and /. Non‑POSIX. May be negated. echoctl, ctlecho Echo control characters in hat notation (^C) instead of literally. Non‑POSIX. May be negated. echoke, crtkill Echo the kill special character by erasing each character on the line as indicated by the echoprt and echoe settings, instead of by the echoctl and echok settings. Non‑POSIX. May be negated. extproc Enable LINEMODE, which is used to avoid echoing each character over high latency links. See also Internet RFC 1116 (https://tools.ietf.org/search/rfc1116). Non‑POSIX. May be negated. flusho Discard output. Note this setting is currently ignored on GNU/Linux systems. Non‑POSIX. May be negated.

🔗 Combination Settings

evenp, parity Same as parenb -parodd cs7. May be negated. If negated, same as -parenb cs8. oddp Same as parenb parodd cs7. May be negated. If negated, same as -parenb cs8. nl Same as -icrnl -onlcr. May be negated. If negated, same as icrnl -inlcr -igncr onlcr -ocrnl -onlret. ek Reset the erase and kill special characters to their default values. sane Same as:

cread -ignbrk brkint -inlcr -igncr icrnl
icanon iexten echo echoe echok -echonl -noflsh
-ixoff -iutf8 -iuclc -ixany imaxbel -xcase -olcuc -ocrnl
opost -ofill onlcr -onocr -onlret nl0 cr0 tab0 bs0 vt0 ff0
isig -tostop -ofdel -echoprt echoctl echoke -extproc

and also sets all special characters to their default values. cooked Same as brkint ignpar istrip icrnl ixon opost isig icanon, plus sets the eof and eol characters to their default values if they are the same as the min and time characters. May be negated. If negated, same as raw. raw Same as:

-ignbrk -brkint -ignpar -parmrk -inpck -istrip
-inlcr -igncr -icrnl -ixon -ixoff -icanon -opost
-isig -iuclc -ixany -imaxbel -xcase min 1 time 0

May be negated. If negated, same as cooked. cbreak Same as -icanon. May be negated. If negated, same as icanon. pass8 Same as -parenb -istrip cs8. May be negated. If negated, same as parenb istrip cs7. litout Same as -parenb -istrip -opost cs8. May be negated. If negated, same as parenb istrip opost cs7. decctlq Same as -ixany. Non‑POSIX. May be negated. tabs Same as tab0. Non‑POSIX. May be negated. If negated, same as tab3. lcase, LCASE Same as xcase iuclc olcuc. Non‑POSIX. May be negated. (Used for terminals with uppercase characters only.) crt Same as echoe echoctl echoke. dec Same as echoe echoctl echoke -ixany intr ^C erase ^? kill C-u.

⌨️ Special Characters

The special characters' default values vary from system to system. They are set with the syntax name value, where the names are listed below and the value can be given either literally, in hat notation (^C), or as an integer which may start with 0x to indicate hexadecimal, 0 to indicate octal, or any other digit to indicate decimal.

For GNU stty, giving a value of ^- or undef disables that special character. (This is incompatible with Ultrix stty, which uses a value of u to disable a special character. GNU stty treats a value u like any other, namely to set that special character to <U>.)

intr Send an interrupt signal. quit Send a quit signal. erase Erase the last character typed. kill Erase the current line. eof Send an end of file (terminate the input). eol End the line. eol2 Alternate character to end the line. Non‑POSIX. discard Alternate character to toggle discarding of output. Non‑POSIX. swtch Switch to a different shell layer. Non‑POSIX. status Send an info signal. Not currently supported on Linux. Non‑POSIX. start Restart the output after stopping it. stop Stop the output. susp Send a terminal stop signal. dsusp Send a terminal stop signal after flushing the input. Non‑POSIX. rprnt Redraw the current line. Non‑POSIX. werase Erase the last word typed. Non‑POSIX. lnext Enter the next character typed literally, even if it is a special character. Non‑POSIX.

✨ Special Settings

min N Set the minimum number of characters that will satisfy a read until the time value has expired, when -icanon is set. time N Set the number of tenths of a second before reads time out if the minimum number of characters have not been read, when -icanon is set. ispeed N Set the input speed to N. ospeed N Set the output speed to N. rows N Tell the tty kernel driver that the terminal has N rows. Non‑POSIX. cols N, columns N Tell the kernel that the terminal has N columns. Non‑POSIX. drain Apply settings after first waiting for pending output to be transmitted. This is enabled by default for GNU stty. It is useful to disable this option in cases where the system may be in a state where serial transmission is not possible. For example, if the system has received the DC3 character with ixon (software flow control) enabled, then stty would block without -drain being specified. May be negated. Non‑POSIX. size Print the number of rows and columns that the kernel thinks the terminal has. (Systems that don't support rows and columns in the kernel typically use the environment variables LINES and COLUMNS instead; however, GNU stty does not know anything about them.) Non‑POSIX. line N Use line discipline N. Non‑POSIX. speed Print the terminal speed. N Set the input and output speeds to N. N can be one of: 0 50 75 110 134 134.5 150 200 300 600 1200 1800 2400 4800 9600 19200 38400 exta extb. exta is the same as 19200; extb is the same as 38400. Many systems, including GNU/Linux, support higher speeds. The stty command includes support for speeds of 57600, 115200, 230400, 460800, 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000, 3000000, 3500000, or 4000000 where the system supports these. 0 hangs up the line if -clocal is set.

🚪 Exit Codes

An exit status of zero indicates success, and a nonzero value indicates failure.

📟 stty: Print or change terminal characteristics 🚀 Quick Reference 📋 Synopsis 📖 Description ⚙️ Options 🎛️ Control Settings 📥 Input Settings 📤 Output Settings 🏠 Local Settings 🔗 Combination Settings ⌨️ Special Characters ✨ Special Settings 🚪 Exit Codes