---
name: "stty"
section: "1"
platform: "macos"
package: "adv_cmds"
version: "237"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "openbsd", "macos"]
url: "https://new.carta.tech/stty"
---

# stty(1)

set the options for a terminal device interface

## NAME

**stty** – set the options for a terminal device interface

## SYNOPSIS

**stty** \[**-a** \| **-e** \| **-g**\] \[**-f** *file*\] \[*arguments*\]

## DESCRIPTION

The **stty** utility sets or reports on terminal characteristics for the device that is its standard input. If no options or arguments 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 following options are available:

- **-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**

  Open and use the terminal named by *file* rather than using standard input. The file is opened using the O\_NONBLOCK flag of **open**(), 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:

Control mode flags affect hardware characteristics associated with the terminal. This corresponds to the c\_cflag in the termios structure.

- *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.

- **clocal** (**-clocal**)

  Assume a line without (with) modem control.

- **cread** (**-cread**)

  Enable (disable) the receiver.

- **crtscts** (**-crtscts**)

  Enable (disable) RTS/CTS flow control.

- **cs5** **cs6** **cs7** **cs8**

  Select character size, if possible.

- **cstopb** (**-cstopb**)

  Use two (one) stop bits per character.

- **hup** (**-hup**)

  Same as **hupcl** (**-hupcl**).

- **hupcl** (**-hupcl**)

  Stop asserting modem control (do not stop asserting modem control) on last close.

- **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.

- **parenb** (**-parenb**)

  Enable (disable) parity generation and detection.

- **parodd** (**-parodd**)

  Select odd (even) parity.

- **speed** *number*

  This sets both **ispeed** and **ospeed** to *number*.

### Input Modes:

This corresponds to the c\_iflag in the termios structure.

- **brkint** (**-brkint**)

  Signal (do not signal) INTR on break.

- **icrnl** (**-icrnl**)

  Map (do not map) CR to NL on input.

- **ignbrk** (**-ignbrk**)

  Ignore (do not ignore) break on input.

- **igncr** (**-igncr**)

  Ignore (do not ignore) CR on input.

- **ignpar** (**-ignpar**)

  Ignore (do not ignore) characters with parity errors.

- **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.

- **inlcr** (**-inlcr**)

  Map (do not map) NL to CR on input.

- **inpck** (**-inpck**)

  Enable (disable) input parity checking.

- **istrip** (**-istrip**)

  Strip (do not strip) input characters to seven bits.

- **iutf8** (**-iutf8**)

  Assume input characters are UTF-8 encoded.

- **ixany** (**-ixany**)

  Allow any character (allow only START) to restart output.

- **ixoff** (**-ixoff**)

  Request that the system send (not send) START/STOP characters when the input queue is nearly empty/full.

- **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.

- **parmrk** (**-parmrk**)

  Mark (do not mark) characters with parity errors.

### Output Modes:

This corresponds to the c\_oflag of the termios structure.

- **bs0** **bs1**

  Select the style of delay for backspaces (e.g., set BSDLY to BS0).

- **cr0** **cr1** **cr2** **cr3**

  Select the style of delay for carriage returns (e.g., set CRDLY to CR0).

- **ff0** **ff1**

  Select the style of delay for form feeds (e.g., set FFDLY to FF0).

- **nl0** **nl1**

  Select the style of delay for newlines (e.g., set NLDLY to NL0).

- **ocrnl** (**-ocrnl**)

  Map (do not map) carriage return to newline on output.

- **ofdel** (**-odell**)

  Use DELs (NULs) as fill characters.

- **ofill** (**-ofill**)

  Use fill characters (use timing) for delays.

- **onlcr** (**-onlcr**)

  Map (do not map) NL to CR-NL on output.

- **onlret** (**-onlret**)

  On the terminal, NL performs (does not perform) the CR function.

- **onocr** (**-onocr**)

  Do not (do) output CRs at column zero.

- **opost** (**-opost**)

  Post-process output (do not post-process output; ignore all other output modes).

- **oxtabs** (**-oxtabs**)

  Expand (do not expand) tabs to spaces on output.

- **tab0** **tab1** **tab2** **tab3**

  Select the style of delay for horizontal tabs (e.g., set TABDLY to TAB0).

- **tabs** (**-tabs**)

  Same as **tab0** (**tab3**).

- **vt0** **vt1**

  Select the style of delay for vertical tabs (e.g., set VTDLY to VT0).

### Local Modes:

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.

- **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.)

- **echo** (**-echo**)

  Echo back (do not echo back) every character typed.

- **echoctl** (**-echoctl**)

  If **echoctl** is set, echo control characters as ^X. Otherwise, control characters echo as themselves.

- **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.

- **echoprt** (**-echoprt**)

  For printing terminals. If set, echo erased characters backwards within \`\`\\'' and \`\`/''. Otherwise, disable this feature.

- **flusho** (**-flusho**)

  Indicates output is (is not) being discarded.

- **icanon** (**-icanon**)

  Enable (disable) canonical input (ERASE and KILL processing).

- **iexten** (**-iexten**)

  Enable (disable) any implementation-defined special control characters that are not currently controlled by **icanon**, **isig**, **ixoff**, or **ixon**.

- **isig** (**-isig**)

  Enable (disable) the checking of characters against the special control characters INTR, QUIT, and SUSP.

- **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.)

- **noflsh** (**-noflsh**)

  Disable (enable) flush after INTR, QUIT, or SUSP.

- **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 becomes pending or more input arrives.

- **tostop** (**-tostop**)

  Send (do not send) SIGTTOU for background output. This causes background jobs to stop if they attempt terminal output.

### 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 (i.e., set to {\_POSIX\_VDISABLE}.)

  Recognized control-characters:

  | | | |
  | --- | --- | --- |
  | control- |  |  |
  | character | Subscript | Description |
  | \_\_\_\_\_\_\_\_\_ | \_\_\_\_\_\_\_\_\_ | \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ |
  | eof | VEOF | EOF character |
  | eol | VEOL | EOL character |
  | eol2 | VEOL2 | EOL2 character |
  | erase | VERASE | ERASE character |
  | erase2 | VERASE2 | ERASE2 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:

- *saved* *settings*

  Set the current terminal characteristics to the saved settings produced by the **-g** option.

- **cols** *number*

  Same as **columns**.

- **columns** *number*

  The terminal size is recorded as having *number* columns.

- **crt** (**-crt**)

  Set (disable) all modes suitable for a CRT display device.

- **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.)

- **ek**

  Reset ERASE, ERASE2, and KILL characters back to system defaults.

- **-evenp**

  Same as **-oddp** and **-parity**.

- **evenp**

  Enable **parenb** and **cs7**; disable **parodd**.

- **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.

- **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.

- **nl** (**-nl**)

  Enable (disable) **icrnl**. In addition, **-nl** unsets **inlcr** and **igncr**.

- **-oddp**

  Same as **-evenp** and **-parity**.

- **oddp**

  Enable **parenb**, **cs7**, and **parodd**.

- **-parity**

  Disable **parenb**; set **cs8**.

- **parity**

  Same as **evenp**.

- **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"
  ```

- **rows** *number*

  The terminal size is recorded as having *number* rows.

- **sane**

  Resets all modes to reasonable values for interactive terminal use.

- **size**

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

- **tty**

  Set the line discipline to the standard terminal line discipline TTYDISC.

### Compatibility Modes:

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.

- **brk** *value*

  Same as the control character **eol**.

- **cbreak**

  If set, enables **brkint**, **ixon**, **imaxbel**, **opost**, **isig**, **iexten**, and **-icanon**. If unset, same as **sane**.

- **cooked**

  Same as **sane**.

- **crtbs** (**-crtbs**)

  Same as **echoe**.

- **crterase** (**-crterase**)

  Same as **echoe**.

- **crtkill** (**-crtkill**)

  Same as **echoke**.

- **ctlecho** (**-ctlecho**)

  Same as **echoctl**.

- **decctlq** (**-decctlq**)

  The converse of **ixany**.

- **everything**

  Same as **all**.

- **flush** *value*

  Same as the control character **discard**.

- **litout** (**-litout**)

  The converse of **opost**.

- **new**

  Same as **tty**.

- **newcrt** (**-newcrt**)

  Same as **crt**.

- **old**

  Same as **tty**.

- **oxtabs** (**-oxtabs**)

  Expand(do not expand) tabs to spaces on output.

- **pass8**

  The converse of **parity**.

- **prterase** (**-prterase**)

  Same as **echoprt**.

- **rprnt** *value*

  Same as the control character **reprint**.

- **tabs** (**-tabs**)

  The converse of **oxtabs**.

- **tandem** (**-tandem**)

  Same as **ixoff**.

## EXIT STATUS

The **stty** utility exits 0 on success, and \>0 if an error occurs.

## LEGACY DESCRIPTION

In legacy operation, the **bs\[01\]**, **cr\[0-3\]**, **ff\[01\]**, **nl\[01\]**, **tab\[0-3\]**, and **vt\[01\]** control modes are not accepted, nor are **ocrnl** (**-ocrnl**), **ofdel** (**-ofdel**), **ofill** (**-ofill**), **onlret** (**-onlret**), and **onocr** (**-onocr**).

For more information about legacy mode, see [compat(5)](/compat/5.md).

## SEE ALSO

[termios(4)](/termios/4.md), [compat(5)](/compat/5.md)

## STANDARDS

The **stty** utility is expected to be IEEE Std 1003.2 (“POSIX.2”) compatible. The flags **-e** and **-f** are extensions to the standard.

## HISTORY

A **stty** command appeared in Version 2 AT&T UNIX.