Sets, resets, and reports workstation operating parameters.
stty [ -a ] [ -g ] [ Options ]
The stty command sets certain I/O options for the device that is the current standard input. This command writes output to the device that is the current standard output.
This version of AIX uses the standard XPG4 interface to control the terminals, maintaining a compatibility with POSIX and BSD interfaces. The stty command supports both POSIX and BSD compliant options, but the usage of POSIX options is strongly recommended. A list of obsolete BSD options, with the corresponding POSIX options, is also provided.
When you redirect standard input from a tty device by entering
stty -a </dev/ttyx
the stty command (POSIX) will hang while waiting for the open() of that tty until the RS-232 carrier detect signal has been asserted. Exceptions to this rule occur if the clocal or forcedcd (128-port only) option is set.
| -a | Writes the current state of all option settings to standard output. |
| -g | Writes option settings to standard output in a form usable by another stty command. |
The stty command supports following categories of options:
| Control Modes | |
|---|---|
| clocal | Assumes a line without modem control. |
| -clocal | Assumes a line with modem control. |
| cread | Enables the receiver. |
| -cread | Disables the receiver. |
| cstopb | Selects 2 stop bits per character. |
| -cstopb | Selects 1 stop bit per character. |
| cs5, cs6, cs7, cs8 | Selects character size. |
| hup, hupcl | Hangs up dial-up connection on the last close. |
| -hup, -hupcl | Does not hang up dial-up connection on the last close. |
| parenb | Enables parity generation and detection. |
| -parenb | Disables parity generation and detection. |
| parodd | Selects odd parity. |
| -parodd | Selects even parity. |
| 0 | Hangs up phone line immediately. |
| speed | Sets the workstation input and output speeds to the specified speed number of bits per second. All speeds are not supported by all hardware interfaces. Possible values for speed are: 50, 75, 110, 134, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 19.2, 38400, 38.4, exta, and extb.
Note: exta, 19200, and 19.2 are synonyms; extb, 38400, and 38.4 are synonyms. |
| ispeed speed | Sets the workstation input speed to the specified speed number of bits per second. All speeds are not supported by all hardware interfaces, and all hardware interfaces do not support this option. Possible values for speed are the same as for the speed option. |
| ospeed speed | Sets the workstation output speed to the specified speed number of bits per second. All speeds are not supported by all hardware interfaces, and all hardware interfaces do not support this option. Possible values for speed are the same as for the speed option. |
| Input Modes | |
| brkint | Signals INTR on break. |
| -brkint | Does not signal INTR on break. |
| icrnl | Maps CR to NL on input. |
| -icrnl | Does not map CR to NL on input. |
| ignbrk | Ignores BREAK on input. |
| -ignbrk | Does not ignore BREAK on input. |
| igncr | Ignores CR on input. |
| -igncr | Does not ignore CR on input. |
| ignpar | Ignores parity errors. |
| -ignpar | Does not ignore parity errors. |
| inlcr | Maps NL to CR on input. |
| -inlcr | Does not map NL to CR on input. |
| inpck | Enables parity checking. |
| -inpck | Disables parity checking. |
| istrip | Strips input characters to 7 bits. |
| -istrip | Does not strip input characters to 7 bits. |
| iuclc | Maps uppercase alphabetic characters to lowercase. |
| -iuclc | Does not map uppercase alphabetic characters to lowercase. |
| ixany | Allows any character to restart output. |
| -ixany | Allows only the START (the Ctrl-Q key sequence) to restart output. |
| ixoff | Sends START/STOP characters when the input queue is nearly empty/full. |
| -ixoff | Does not send START/STOP characters. |
| ixon | Enables START/STOP output control. Once START/STOP output control has been enabled, you can pause output to the workstation by pressing the Ctrl-S key sequence and resume output by pressing the Ctrl-Q key sequence. |
| -ixon | Disables START/STOP output control. |
| imaxbel | Echoes the BEL character and discards the last input character if input overflows. |
| -imaxbel | Discards all input if input overflows. |
| parmrk | Marks parity errors. |
| -parmrk | Does not mark parity errors. |
| Output Modes | |
| bs0, bs1 | Selects style of delay for backspaces (bs0 siginifes no delay). |
| cr0, cr1, cr2, cr3 | Selects style of delay for CR characters (cr0 siginifes no delay). |
| ff0, ff1 | Selects style of delay for form feeds (ff0 siginifes no delay). |
| nl0, nl1 | Selects style of delay for NL characters (nl0 siginifes no delay). |
| ofill | Uses fill characters for delays. |
| -ofill | Uses timing for delays. |
| ocrnl | Maps CR characters to NL characters. |
| -ocrnl | Does not map CR characters to NL characters. |
| olcuc | Maps lowercase alphabetic characters to uppercase on output. |
| -olcuc | Does not map lowercase alphabetic characters to uppercase on output. |
| onlcr | Maps NL characters to CR-NL characters. |
| -onlcr | Does not map NL characters to CR-NL characters. |
| onlret | On the terminal, NL performs the CR function. |
| -onlret | On the terminal, NL does not perform the CR function. |
| onocr | Does not output CR characters at column zero. |
| -onocr | Outputs CR characters at column zero. |
| opost | Processes output. |
| -opost | Does not process output; that is, ignores all other output options. |
| ofdel | Uses DEL characters for fill characters. |
| -ofdel | Uses NUL characters for fill characters. |
| tab0, tab1, tab2 | Selects style of delay for horizontal tabs (tab0 siginifes no delay). |
| tab3 | Expands tab character to variable number of spaces. |
| vt0, vt1 | Selects style of delay for vertical tabs (vt0 siginifes no delay). |
| Local Modes | |
| echo | Echoes every character typed. |
| -echo | Does not echo characters. |
| echoctl | Echoes control characters as ^X (Ctrl-X), where X is the character given by adding 100 octal to the code of the control character. |
| -echoctl | Does not echo control characters as ^X (Ctrl-X). |
| echoe | Echoes the ERASE character as the "backspace space backspace" string.
Note: This mode does not keep track of column position, so you can get unexpected results when erasing such things as tabs and escape sequences. |
| -echoe | Does not echo the ERASE character, just backspace. |
| echok | Echoes a NL character after a KILL character. |
| -echok | Does not echo a NL character after a KILL character. |
| echoke | Echoes the KILL character by erasing each character on the output line. |
| -echoke | Just echoes the KILL character. |
| echonl | Echoes the NL character. |
| -echonl | Does not echo the NL character. |
| echoprt | Echoes erased characters backwards with / (slash) and \ (backslash). |
| -echoprt | Does not echo erased characters backwards with / (slash) and \ (backslash). |
| icanon | Enables canonical input (canonical input allows input-line editing with the ERASE and KILL characters). See the discussion about canonical mode input in Line Discipline Module (ldterm) AIX Version 4.3 Communications Programming Concepts. |
| -icanon | Disables canonical input. |
| iexten | Specifies that implementation-defined functions shall be recognized from the input data. Recognition of the following control characters requires iexten to be set: eol2, dsusp, reprint, discard, werase, lnext. The functions associated with these modes also require iexten to be set: imaxbel, echoke, echoprt, and echoctl. |
| -iexten | Specifies that implementation-defined functions shall not be recognized from the input data. |
| isig | Enables the checking of characters against the special control characters INTR, SUSP and QUIT special control characters. |
| -isig | Disables the checking of characters against the special control characters INTR, SUSP and QUIT special control characters. |
| noflsh | Does not clear buffers after INTR, SUSP, or QUIT control characters. |
| -noflsh | Clears buffers after INTR, SUSP, or QUIT control characters. |
| pending | Causes any input that is pending after a switch from raw to canonical mode to be re-input the next time a read operation becomes pending or the next time input arrives. Pending is an internal state bit. |
| -pending | No text is pending. |
| tostop | Signals SIGTOU for background output. |
| -tostop | Does not signal SIGTOU for background output. |
| xcase | Echoes uppercase characters on input, and displays uppercase characters on output with a preceding \ (backslash). |
| -xcase | Does not echo uppercase characters on input. |
These options are extensions to the XPG4 standard.
To assign a control character to a character string, enter:
stty Control String
where the Control parameter may be the INTR, QUIT, ERASE, KILL, EOF, EOL, EOL2, START, STOP, SUSP, DSUSP, REPRINT, DISCARD, WERASE, LNEXT, MIN, or TIME character. (Use the MIN and TIME characters with the -icanon option.)
Note: The values for MIN and TIME are interpreted as integer values, not as character values.
The String parameter may be any single character such as c. An example of this control assignment is:
stty STOP c
Another way of assigning control characters is to enter a character sequence composed of a \^ (backslash, circumflex) followed by a single character. If the single character after the ^ (circumflex) is one of the characters listed in the ^c (circumflex c) column of the following table, the corresponding control character value will be set. For example, to assign the DEL control character by using the ? (question mark) character, enter the string \^? (backslash, circumflex, question mark), as in:
stty ERASE \^?
| Circumflex Control Characters in stty | |||||
| ^c | Value | ^c | Value | ^c | Value |
| a, A | <SOH> | l, L | <FF> | w, W | <ETB> |
| b, B | <STX> | m, M | <CR> | x, X | <CAN> |
| c, C | <ETX> | n, N | <SO> | y, Y | <EM> |
| d, D | <EOT> | o, O | <SI> | z, Z | <SUB> |
| e, E | <ENQ> | p, P | <DLE> | [ | <ESC> |
| f, F | <ACK> | q, Q | <DC1> | \ | <FS> |
| g, G | <BEL> | r, R | <DC2> | ] | <GS> |
| h, H | <BS> | s, S | <DC3> | ^ | <RS> |
| i, I | <HT> | t, T | <DC4> | _ | <US> |
| j, J | <LF> | u, U | <NAK> | ? | <DEL> |
| k, K | <VT> | v, V | <SYN> | @ | <NUL> |
| Combination Modes | |
|---|---|
| cooked | See the -raw option. |
| ek | Sets ERASE and KILL characters to the Ctrl-H and Ctrl-U key sequences, respectively. |
| evenp | Enables parenb and cs7. |
| -evenp | Disables parenb and sets cs8. |
| lcase, LCASE | Sets xcase, iuclc, and olcuc. Used for workstations with uppercase characters only. |
| -lcase, -LCASE | Sets -xcase, -iuclc, and -olcuc. |
| nl | Sets -icrnl and -onlcr. |
| -nl | Sets icrnl, onlcr, -inlcr, -igncr, -ocrnl, and -onlret. |
| oddp | Enables parenb, cs7, and parodd. |
| -oddp | Disables parenb and sets cs8. |
| parity | See the evenp option. |
| -parity | See the -evenp option. |
| sane | Resets parameters to reasonable values. |
| raw | Allows raw mode input (no input processing, such as erase, kill, or interrupt); parity bit passed back. |
| -raw | Allows canonical input mode. |
| tabs | Preserves tabs. |
| -tabs, tab3 | Replaces tabs with spaces when printing. |
The following BSD options are supported by the stty command. For each of them, the recommended POSIX option is given.
| all | Use the stty -a command to display all current settings. |
| crt | Use the sane option to reset parameters to reasonable values. |
| crtbs | Use the -echoe option. |
| crterase | Use the echoe option. |
| -crterase | Use the -echoe option. |
| crtkill | Use the echoke option. |
| -crtkill | Use the echok and -echoke options. |
| ctlecho | Use the echoctl option. |
| -ctlecho | Use the -echoctl option. |
| decctlq | Use the -ixany option. |
| -decctlq | Use the ixany option. |
| even | Use the evenp option. |
| -even | Use the -evenp option. |
| everything | Use the stty -a command to display all current settings. |
| litout | Use the -opost option. |
| -litout | Use the opost option. |
| odd | Use the oddp option. |
| -odd | Use the -oddp option. |
| pass8 | Use the -istrip option. |
| -pass8 | Use the istrip option. |
| prterase | Use the echoprt option. |
| speed | Use the stty command to display current settings. |
| tandem | Use the ixoff option. |
| -tandem | Use the -ixoff option. |
sttyThis lists settings that differ from the defaults.
stty -a
stty ixon ixanyThis sets ixon mode, which lets you stop runaway listing by pressing the Ctrl-S key sequence. The ixany flag allows you to resume the listing by pressing any key. The normal workstation configuration includes the ixon and ixany flags, which allows you to stop a listing with the Ctrl-S key sequence that only the Ctrl-Q key sequence will restart.
Ctrl-J stty sane Ctrl-JPress the Ctrl-J key sequence before and after the command instead of the Enter key. The system usually recognizes the Ctrl-J key sequence when the parameters that control Enter key processing are messed up.
Sometimes the information displayed on the screen may look strange, or the system will not respond when you press the Enter key. This can happen when you use the stty command with parameters that are incompatible or that do things you don't understand. It can also happen when a screen-oriented application ends abnormally and does not have a chance to reset the workstation configuration.
Entering the stty sane command sets a reasonable configuration, but it may differ slightly from your normal configuration.
OLDCONFIG=`stty -g` # save configuration stty -echo # do not display password echo "Enter password: \c" read PASSWD # get the password stty $OLDCONFIG # restore configurationThis command saves the workstation's configuration, turns off echoing, reads a password, and restores the original configuration.
Entering the stty -echo command turns off echoing, which means that the password does not appear on the screen when you type it at the keyboard. This action has nothing to do with the echo command, which displays a message on the screen.
| /usr/bin/stty | Contains the stty command. |
The terminfo file, tty special file termios.h header file.
National Language Support Overview for Programming and TTY Subsystem Overview in AIX Version 4.3 General Programming Concepts: Writing and Debugging Programs.
ldterm Line Discipline in AIX General Programming Concepts: Writing and Debugging Programs.