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1 .\" $NetBSD: stty.1,v 1.37 2009/12/14 02:34:52 dholland Exp $
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33 .\" @(#)stty.1 8.5 (Berkeley) 6/1/94
34 .\"
35 .Dd December 14, 2009
36 .Dt STTY 1
37 .Os
38 .Sh NAME
39 .Nm stty
40 .Nd set the options for a terminal device interface
41 .Sh SYNOPSIS
42 .Nm
43 .Op Fl a | Fl e | Fl g
44 .Op Fl f Ar file
45 .Op operands
46 .Sh DESCRIPTION
47 The
48 .Nm
49 utility sets or reports on terminal
50 characteristics for the device that is its standard input.
51 If no options or operands are specified, it reports the settings of a subset
52 of characteristics as well as additional ones if they differ from their
53 default values.
54 Otherwise it modifies
55 the terminal state according to the specified arguments.
56 Some combinations of arguments are mutually
57 exclusive on some terminal types.
58 .Pp
59 The following options are available:
60 .Bl -tag -width Ds
61 .It Fl a
62 Display all the current settings for the terminal to standard output
63 as per
64 .St -p1003.2 .
65 .It Fl e
66 Display all the current settings for the terminal to standard output
67 in the traditional
68 .Bx
69 ``all'' and ``everything'' formats.
70 .It Fl f
71 Open and use the terminal named by
72 .Ar file
73 rather than using standard input.
74 The file is opened using the
75 .Dv O_NONBLOCK
76 flag of
77 .Fn open ,
78 making it possible to
79 set or display settings on a terminal that might otherwise
80 block on the open.
81 .It Fl g
82 Display all the current settings for the terminal to standard output
83 in a form that may be used as an argument to a subsequent invocation of
84 .Nm
85 to restore the current terminal state as per
86 .St -p1003.2 .
87 .El
88 .Pp
89 The following arguments are available to set the terminal
90 characteristics:
91 .Ss Control Modes
92 Control mode flags affect hardware characteristics associated with the
93 terminal.
94 This corresponds to the c_cflag in the termios structure.
95 .Bl -tag -width Fl
96 .It Cm parenb Pq Fl parenb
97 Enable (disable) parity generation
98 and detection.
99 .It Cm parodd Pq Fl parodd
100 Select odd (even) parity.
101 .It Cm cs5 cs6 cs7 cs8
102 Select character size, if possible.
103 .It Ar number
104 Set terminal baud rate to the
105 number given, if possible.
106 If the
107 baud rate is set to zero, modem
108 control is no longer
109 asserted.
110 .It Cm ispeed Ar number
111 Set terminal input baud rate to the
112 number given, if possible.
113 If the
114 input baud rate is set to zero, the
115 input baud rate is set to the
116 value of the output baud
117 rate.
118 .It Cm ospeed Ar number
119 Set terminal output baud rate to
120 the number given, if possible.
121 If
122 the output baud rate is set to
123 zero, modem control is
124 no longer asserted.
125 .It Cm speed Ar number
126 This sets both
127 .Cm ispeed
128 and
129 .Cm ospeed
130 to
131 .Ar number .
132 .It Cm hupcl Pq Fl hupcl
133 Stop asserting modem control
134 (do not stop asserting modem control) on last close.
135 .It Cm hup Pq Fl hup
136 Same as hupcl
137 .Pq Fl hupcl .
138 .It Cm cstopb Pq Fl cstopb
139 Use two (one) stop bits per character.
140 .It Cm cread Pq Fl cread
141 Enable (disable) the receiver.
142 .It Cm clocal Pq Fl clocal
143 Assume a line without (with) modem
144 control.
145 .It Cm crtscts Pq Fl crtscts
146 Enable RTS/CTS flow control.
147 .It Cm cdtrcts Pq Fl cdtrcts
148 Enable DTR/CTS flow control (if supported).
149 .El
150 .Ss Input Modes
151 This corresponds to the c_iflag in the termios structure.
152 .Bl -tag -width Fl
153 .It Cm ignbrk Pq Fl ignbrk
154 Ignore (do not ignore) break on
155 input.
156 .It Cm brkint Pq Fl brkint
157 Signal (do not signal)
158 .Dv INTR
159 on
160 break.
161 .It Cm ignpar Pq Fl ignpar
162 Ignore (do not ignore) parity
163 errors.
164 .It Cm parmrk Pq Fl parmrk
165 Mark (do not mark) parity errors.
166 .It Cm inpck Pq Fl inpck
167 Enable (disable) input parity
168 checking.
169 .It Cm istrip Pq Fl istrip
170 Strip (do not strip) input characters
171 to seven bits.
172 .It Cm inlcr Pq Fl inlcr
173 Map (do not map)
174 .Dv NL
175 to
176 .Dv CR
177 on input.
178 .It Cm igncr Pq Fl igncr
179 Ignore (do not ignore)
180 .Dv CR
181 on input.
182 .It Cm icrnl Pq Fl icrnl
183 Map (do not map)
184 .Dv CR
185 to
186 .Dv NL
187 on input.
188 .It Cm ixon Pq Fl ixon
189 Enable (disable)
190 .Dv START/STOP
191 output
192 control.
193 Output from the system is
194 stopped when the system receives
195 .Dv STOP
196 and started when the system
197 receives
198 .Dv START ,
199 or if
200 .Cm ixany
201 is set, any character restarts output.
202 .It Cm ixoff Pq Fl ixoff
203 Request that the system send (not
204 send)
205 .Dv START/STOP
206 characters when
207 the input queue is nearly
208 empty/full.
209 .It Cm ixany Pq Fl ixany
210 Allow any character (allow only
211 .Dv START )
212 to restart output.
213 .It Cm imaxbel Pq Fl imaxbel
214 The system imposes a limit of
215 .Dv MAX_INPUT
216 (currently 255) characters in the input queue.
217 If
218 .Cm imaxbel
219 is set and the input queue limit has been reached,
220 subsequent input causes the system to send an ASCII BEL
221 character to the output queue (the terminal beeps at you).
222 Otherwise,
223 if
224 .Cm imaxbel
225 is unset and the input queue is full, the next input character causes
226 the entire input and output queues to be discarded.
227 .El
228 .Ss Output Modes
229 This corresponds to the c_oflag of the termios structure.
230 .Bl -tag -width Fl
231 .It Cm opost Pq Fl opost
232 Post-process output (do not
233 post-process output; ignore all other
234 output modes).
235 .It Cm onlcr Pq Fl onlcr
236 Map (do not map)
237 .Dv NL
238 to
239 .Dv CR-NL
240 on output.
241 .It Cm ocrnl Pq Fl ocrnl
242 Map (do not map)
243 .Dv CR
244 to
245 .Dv NL
246 on output.
247 .It Cm oxtabs Pq Fl oxtabs
248 Expand (do not expand) tabs to spaces on output.
249 .It Cm onocr Pq Fl onocr
250 Do not (do) output CRs at column zero.
251 .It Cm onlret Pq Fl onlret
252 On the terminal NL performs (does not perform) the CR function.
253 .El
254 .Ss Local Modes
255 Local mode flags (lflags) affect various and sundry characteristics of terminal
256 processing.
257 Historically the term "local" pertained to new job control features
258 implemented by Jim Kulp on a
259 .Tn PDP Ns -11/70
260 at
261 .Tn IIASA .
262 Later the driver ran on the first
263 .Tn VAX
264 at Evans Hall, UC Berkeley, where the job control details
265 were greatly modified but the structure definitions and names
266 remained essentially unchanged.
267 The second interpretation of the 'l' in lflag
268 is ``line discipline flag'' which corresponds to the
269 .Ar c_lflag
270 of the
271 .Ar termios
272 structure.
273 .Bl -tag -width Fl
274 .It Cm isig Pq Fl isig
275 Enable (disable) the checking of
276 characters against the special control
277 characters
278 .Dv INTR , QUIT ,
279 and
280 .Dv SUSP .
281 .It Cm icanon Pq Fl icanon
282 Enable (disable) canonical input
283 .Pf ( Dv ERASE
284 and
285 .Dv KILL
286 processing).
287 .It Cm iexten Pq Fl iexten
288 Enable (disable) any implementation
289 defined special control characters
290 not currently controlled by icanon,
291 isig, or ixon.
292 .It Cm echo Pq Fl echo
293 Echo back (do not echo back) every
294 character typed.
295 .It Cm echoe Pq Fl echoe
296 The
297 .Dv ERASE
298 character shall (shall
299 not) visually erase the last character
300 in the current line from the
301 display, if possible.
302 .It Cm echok Pq Fl echok
303 Echo (do not echo)
304 .Dv NL
305 after
306 .Dv KILL
307 character.
308 .It Cm echoke Pq Fl echoke
309 The
310 .Dv KILL
311 character shall (shall
312 not) visually erase
313 the current line from the
314 display, if possible.
315 .It Cm echonl Pq Fl echonl
316 Echo (do not echo)
317 .Dv NL ,
318 even if echo
319 is disabled.
320 .It Cm echoctl Pq Fl echoctl
321 If
322 .Cm echoctl
323 is set, echo control characters as ^X.
324 Otherwise control characters echo as themselves.
325 .It Cm echoprt Pq Fl echoprt
326 For printing terminals.
327 If set, echo erased characters backwards within ``\\''
328 and ``/''.
329 Otherwise, disable this feature.
330 .It Cm noflsh Pq Fl noflsh
331 Disable (enable) flush after
332 .Dv INTR , QUIT , SUSP .
333 .It Cm tostop Pq Fl tostop
334 Send (do not send)
335 .Dv SIGTTOU
336 for background output.
337 This causes background jobs to stop if they attempt terminal output.
338 .It Cm altwerase Pq Fl altwerase
339 Use (do not use) an alternative word erase algorithm when processing
340 .Dv WERASE
341 characters.
342 This alternative algorithm considers sequences of
343 alphanumeric/underscores as words.
344 It also skips the first preceding character in its classification
345 (as a convenience since the one preceding character could have been
346 erased with simply an
347 .Dv ERASE
348 character.)
349 .It Cm mdmbuf Pq Fl mdmbuf
350 If set, flow control output based on condition of Carrier Detect.
351 Otherwise writes return an error if Carrier Detect is low (and Carrier
352 is not being ignored with the
353 .Dv CLOCAL
354 flag.)
355 .It Cm flusho Pq Fl flusho
356 Indicates output is (is not) being discarded.
357 .It Cm pendin Pq Fl pendin
358 Indicates input is (is not) pending after a switch from non-canonical
359 to canonical mode and will be re-input when a read becomes pending
360 or more input arrives.
361 .El
362 .Ss Control Characters
363 .Bl -tag -width Fl
364 .It Ar control-character Ar string
365 Set
366 .Ar control-character
367 to
368 .Ar string .
369 If string is a single character,
370 the control character is set to
371 that character.
372 If string is the
373 two character sequence "^-" or the
374 string "undef" the control character
375 is disabled (i.e. set to
376 .Bro Dv _POSIX_VDISABLE Brc . )
377 .Pp
378 Recognized control-characters:
379 .Bd -ragged -offset indent
380 .Bl -column character Subscript Description
381 .It control- Ta "" Ta ""
382 .It character Subscript Description
383 .It _________ _________ _______________
384 .It eof Ta Tn VEOF Ta EOF No character
385 .It eol Ta Tn VEOL Ta EOL No character
386 .It eol2 Ta Tn VEOL2 Ta EOL2 No character
387 .It erase Ta Tn VERASE Ta ERASE No character
388 .It werase Ta Tn VWERASE Ta WERASE No character
389 .It kill Ta Tn VKILL Ta KILL No character
390 .It reprint Ta Tn VREPRINT Ta REPRINT No character
391 .It intr Ta Tn VINTR Ta INTR No character
392 .It quit Ta Tn VQUIT Ta QUIT No character
393 .It susp Ta Tn VSUSP Ta SUSP No character
394 .It dsusp Ta Tn VDSUSP Ta DSUSP No character
395 .It start Ta Tn VSTART Ta START No character
396 .It stop Ta Tn VSTOP Ta STOP No character
397 .It lnext Ta Tn VLNEXT Ta LNEXT No character
398 .It status Ta Tn VSTATUS Ta STATUS No character
399 .It discard Ta Tn VDISCARD Ta DISCARD No character
400 .El
401 .Ed
402 .It Cm min Ar number
403 .It Cm time Ar number
404 Set the value of min or time to
405 number.
406 .Dv MIN
407 and
408 .Dv TIME
409 are used in
410 Non-Canonical mode input processing
411 (-icanon).
412 .El
413 .Ss Combination Modes
414 .Bl -tag -width Fl
415 .It Ar saved settings
416 Set the current terminal characteristics to the saved settings
417 produced by the
418 .Fl g
419 option.
420 .It Cm evenp No or Cm parity
421 Enable parenb and cs7; disable parodd.
422 .It Cm oddp
423 Enable parenb, cs7, and parodd.
424 .It Fl parity , evenp , oddp
425 Disable parenb, and set cs8.
426 .It Cm \&nl Pq Fl \&nl
427 Enable (disable) icrnl.
428 In addition
429 -nl unsets inlcr and igncr.
430 .It Cm ek
431 Reset
432 .Dv ERASE
433 and
434 .Dv KILL
435 characters back to system defaults.
436 .It Cm sane
437 Resets all modes to reasonable values for interactive terminal use.
438 .It Cm insane
439 Sets all modes to random values, which are very likely
440 .Pq but not guaranteed
441 to be unreasonable for interactive terminal use.
442 .It Cm tty
443 Set the line discipline to the standard terminal line discipline
444 .Dv TTYDISC .
445 .It Cm crt Pq Fl crt
446 Set (disable) all modes suitable for a CRT display device.
447 .It Cm kerninfo Pq Fl kerninfo
448 Enable (disable) the system generated status line associated with
449 processing a
450 .Dv STATUS
451 character (usually set to ^T).
452 The status line consists of the
453 system load average, the current command name, its process ID, the
454 event the process is waiting on (or the status of the process), the user
455 and system times, percent CPU, and current memory usage.
456 .It Cm columns Ar number
457 The terminal size is recorded as having
458 .Ar number
459 columns.
460 .It Cm cols Ar number
461 is an alias for
462 .Cm columns .
463 .It Cm rows Ar number
464 The terminal size is recorded as having
465 .Ar number
466 rows.
467 .It Cm dec
468 Set modes suitable for users of Digital Equipment Corporation systems (
469 .Dv ERASE ,
470 .Dv KILL ,
471 and
472 .Dv INTR
473 characters are set to ^?, ^U, and ^C;
474 .Dv ixany
475 is disabled, and
476 .Dv crt
477 is enabled.)
478 .It Cm extproc Pq Fl extproc
479 If set, this flag indicates that some amount of terminal processing is being
480 performed by either the terminal hardware or by the remote side connected
481 to a pty.
482 .It Cm raw Pq Fl raw
483 If set, change the modes of the terminal so that no input or output processing
484 is performed.
485 If unset, change the modes of the terminal to some reasonable
486 state that performs input and output processing.
487 Note that since the terminal driver no longer has a single
488 .Dv RAW
489 bit, it is not possible to intuit what flags were set prior to setting
490 .Cm raw .
491 This means that unsetting
492 .Cm raw
493 may not put back all the setting that were previously in effect.
494 To set the terminal into a raw state and then accurately restore it, the following
495 shell code is recommended:
496 .Bd -literal -offset indent
497 save_state=$(stty -g)
498 stty raw
499 \&...
500 stty "$save_state"
501 .Ed
502 .It Cm size
503 The size of the terminal is printed as two numbers on a single line,
504 first rows, then columns.
505 .El
506 .Ss Compatibility Modes
507 These modes remain for compatibility with the previous version of
508 the stty command.
509 .Bl -tag -width Fl
510 .It Cm all
511 Reports all the terminal modes as with
512 .Cm stty Fl a
513 except that the control characters are printed in a columnar format.
514 .It Cm everything
515 Same as
516 .Cm all .
517 .It Cm cooked
518 Same as
519 .Cm sane .
520 .It Cm cbreak
521 If set, enables
522 .Cm brkint , ixon , imaxbel , opost ,
523 .Cm isig , iexten ,
524 and
525 .Fl icanon .
526 If unset, same as
527 .Cm sane .
528 .It Cm new
529 Same as
530 .Cm tty .
531 .It Cm old
532 Same as
533 .Cm tty .
534 .It Cm newcrt Pq Fl newcrt
535 Same as
536 .Cm crt .
537 .It Cm pass8
538 The converse of
539 .Cm parity .
540 .It Cm tandem Pq Fl tandem
541 Same as
542 .Cm ixoff .
543 .It Cm decctlq Pq Fl decctlq
544 The converse of
545 .Cm ixany .
546 .It Cm crterase Pq Fl crterase
547 Same as
548 .Cm echoe .
549 .It Cm crtbs Pq Fl crtbs
550 Same as
551 .Cm echoe .
552 .It Cm crtkill Pq Fl crtkill
553 Same as
554 .Cm echoke .
555 .It Cm ctlecho Pq Fl ctlecho
556 Same as
557 .Cm echoctl .
558 .It Cm prterase Pq Fl prterase
559 Same as
560 .Cm echoprt .
561 .It Cm litout Pq Fl litout
562 The converse of
563 .Cm opost .
564 .It Cm tabs Pq Fl tabs
565 The converse of
566 .Cm oxtabs .
567 .It Cm brk Ar value
568 Same as the control character
569 .Cm eol .
570 .It Cm flush Ar value
571 Same as the control character
572 .Cm discard .
573 .It Cm rprnt Ar value
574 Same as the control character
575 .Cm reprint .
576 .El
577 .Ss Control operations
578 These operations are not modes, but rather commands to be performed by
579 the tty layer.
580 .Bl -tag -width Fl
581 .It Cm ostart
582 Performs a "start output" operation, as normally done by an
583 incoming START character when
584 .Cm ixon
585 is set.
586 .It Cm ostop
587 Performs a "stop output" operation, as normally done by an
588 incoming STOP character when
589 .Cm ixon
590 is set.
591 .El
592 .Sh EXIT STATUS
593 The
594 .Nm
595 utility exits with a value of 0 if successful, and \*[Gt]0 if an error occurs.
596 .Sh SEE ALSO
597 .Xr termios 4 ,
598 .Xr tty 4
599 .Sh STANDARDS
600 The
601 .Nm
602 utility is expected to be
603 .St -p1003.2
604 compatible.
605 The flags
606 .Fl e
607 and
608 .Fl f
609 are
610 extensions to the standard, as are the operands mentioned in the control
611 operations section.