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STTY(1)                    OpenBSD Reference Manual                    STTY(1)

NAME
     stty - set the options for a terminal device interface

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

DESCRIPTION
     The stty utility sets or reports on terminal characteristics for the de-
     vice that is its standard input.  If no options or operands are speci-
     fied, 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 stan-
             dard input.  The file is opened using the O_NONBLOCK flag of
             open(2), making it possible to set or display settings on a ter-
             minal 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 characteris-
     tics:

   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 as-
                 serted.

     ispeed number
                 Set terminal input baud rate to the number given, if possi-
                 ble.  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 possi-
                 ble.  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
     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 in-
                 put.

     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 char-
                 acter 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) char-
                 acters 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.

     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 out-
                 put.

     olcuc (-olcuc)
                 Translate (do not translate) lower case to upper case on out-
                 put.

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

     onoeot (-onoeot)
                 Discard (do not discard) EOFs on output.

   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.

     isig (-isig)
                 Enable (disable) the checking of characters against the spe-
                 cial 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 cur-
                 rent 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'.  Other-
                 wise control characters echo as themselves.

     echoprt (-echoprt)
                 For printing terminals.  If set, echo erased characters back-
                 wards 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 caus-
                 es background jobs to stop if they attempt terminal output.

     altwerase (-altwerase)
                 Use (do not use) an alternate word erase algorithm when pro-
                 cessing WERASE characters.  This alternate algorithm consid-
                 ers 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 De-
                 tect.  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
                 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

     control-character string
                 Set control-character to string.  If string is a single char-
                 acter, 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
                       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 set-
                 tings 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 termi-
                 nal use.

     tty         Set the line discipline to the standard terminal line disci-
                 pline 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 cur-
                 rent command name, its process ID, the event the process is
                 waiting on (or the status of the process), the user and sys-
                 tem times, percent CPU, and current memory usage.

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

     cols number
                 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 pro-
                 cessing 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 pre-
                 viously in effect.  To set the terminal into a raw state and
                 then accurately restore it, the following shell code is rec-
                 ommended:

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

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

   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.

     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
     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.

SEE ALSO
     termios(4)

STANDARDS
     The stty utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compati-
     ble.  The flags -e and -f are extensions to the standard, as are the
     operands mentioned in the control operations section.

HISTORY
     A stty command appeared in Version 3 AT&T UNIX.

OpenBSD 3.4                      June 1, 1994                                7

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | STANDARDS | HISTORY

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