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           The   Linux  console  implements  a  large  subset  of  the  VT102  and
           ECMA-48/ISO 6429/ANSI X3.64 terminal controls,  plus  certain  private-
           mode  sequences  for changing the color palette, character-set mapping,
           and so on.  In the tabular descriptions below, the second column  gives
           ECMA-48  or  DEC  mnemonics  (the  latter if prefixed with DEC) for the
           given function.  Sequences without a mnemonic are neither  ECMA-48  nor
           After  all  the normal output processing has been done, and a stream of
           characters arrives at the console driver for actual printing, the first
           thing  that  happens is a translation from the code used for processing
           to the code used for printing.
           If the console is in UTF-8 mode, then  the  incoming  bytes  are  first
           assembled  into  16-bit  Unicode  codes.  Otherwise each byte is trans-
           formed according to the current mapping table (which translates it to a
           Unicode value).  See the Character Sets section below for discussion.
           In the normal case, the Unicode value is converted to a font index, and
           this is stored in video memory, so that  the  corresponding  glyph  (as
           found  in  video ROM) appears on the screen.  Note that the use of Uni-
           code (and the design of the PC hardware) allows us to use 512 different
           glyphs simultaneously.
           If  the  current  Unicode  value is a control character, or we are cur-
           rently processing an escape sequence, the value will treated specially.
           Instead  of  being turned into a font index and rendered as a glyph, it
           may trigger cursor movement or other control functions.  See the  Linux
           Console Controls section below for discussion.
           It  is  generally not good practice to hard-wire terminal controls into
           programs.  Linux supports a terminfo(5) database of terminal  capabili-
           ties.   Rather than emitting console escape sequences by hand, you will
           almost always want to use a terminfo-aware screen  library  or  utility
           such as ncurses(3), tput(1), or reset(1).
       Linux console controls
           This  section describes all the control characters and escape sequences
           that invoke special functions (i.e.,  anything  other  than  writing  a
           glyph at the current cursor location) on the Linux console.
           Control characters
           A  character is a control character if (before transformation according
           to the mapping table) it has one of the 14 codes 00 (NUL), 07 (BEL), 08
           (BS), 09 (HT), 0a (LF), 0b (VT), 0c (FF), 0d (CR), 0e (SO), 0f (SI), 18
           (CAN), 1a (SUB), 1b (ESC), 7f (DEL).  One can set  a  "display  control
           characters"  mode  (see  below), and allow 07, 09, 0b, 18, 1a, 7f to be
           displayed as glyphs.  On the other hand, in UTF-8 mode all codes  00-1f
           are  regarded as control characters, regardless of any "display control
           characters" mode.
           HT  (0x09,  ^I)  goes to the next tab stop or to the end of the line if
                  there is no earlier tab stop;
           LF (0x0A, ^J), VT (0x0B, ^K) and FF (0x0C, ^L) all give a linefeed, and
                  if LF/NL (new-line mode) is set also a carriage return;
           CR (0x0D, ^M) gives a carriage return;
           SO (0x0E, ^N) activates the G1 character set;
           SI (0x0F, ^O) activates the G0 character set;
           CAN (0x18, ^X) and SUB (0x1A, ^Z) interrupt escape sequences;
           ESC (0x1B, ^[) starts an escape sequence;
           DEL (0x7F) is ignored;
           CSI (0x9B) is equivalent to ESC [.
           ESC- but not CSI-sequences
           ESC c     RIS      Reset.
           ESC D     IND      Linefeed.
           ESC E     NEL      Newline.
           ESC H     HTS      Set tab stop at current column.
           ESC M     RI       Reverse linefeed.
           ESC Z     DECID    DEC private identification. The kernel returns the
                              string  ESC [ ? 6 c, claiming that it is a  VT102.
           ESC 7     DECSC    Save    current    state    (cursor   coordinates,
                              attributes, character sets pointed at by G0,  G1).
           ESC 8     DECRC    Restore state most recently saved by ESC 7.
           ESC [     CSI      Control sequence introducer
           ESC %              Start sequence selecting character set
           ESC % @               Select default (ISO 646 / ISO 8859-1)
           ESC % G               Select UTF-8
           ESC % 8               Select UTF-8 (obsolete)
           ESC # 8   DECALN   DEC screen alignment test - fill screen with E's.
           ESC (              Start sequence defining G0 character set
           ESC ( B               Select default (ISO 8859-1 mapping)
           ESC ( 0               Select VT100 graphics mapping
           ESC ( U               Select null mapping - straight to character ROM
           ESC ( K               Select user mapping - the map that is loaded by
                                 the utility mapscrn(8).
           ESC )              Start sequence defining G1
                              (followed by one of B, 0, U, K, as above).
           ESC >     DECPNM   Set numeric keypad mode
           ESC =     DECPAM   Set application keypad mode
           ESC ]     OSC      (Should  be:  Operating  system  command)  ESC ] P
                              nrrggbb: set palette, with parameter  given  in  7
                              hexadecimal  digits after the final P :-(.  Here n
                              is the color  (0-15),  and  rrggbb  indicates  the
           The action of a CSI sequence is determined by its final character.
           @   ICH       Insert the indicated # of blank characters.
           A   CUU       Move cursor up the indicated # of rows.
           B   CUD       Move cursor down the indicated # of rows.
           C   CUF       Move cursor right the indicated # of columns.
           D   CUB       Move cursor left the indicated # of columns.
           E   CNL       Move cursor down the indicated # of rows, to column 1.
           F   CPL       Move cursor up the indicated # of rows, to column 1.
           G   CHA       Move cursor to indicated column in current row.
           H   CUP       Move cursor to the indicated row, column (origin at 1,1).
           J   ED        Erase display (default: from cursor to end of display).
                         ESC [ 1 J: erase from start to cursor.
                         ESC [ 2 J: erase whole display.
                         ESC [ 3 J: erase whole display including scroll-back
                                    buffer (since Linux 3.0).
           K   EL        Erase line (default: from cursor to end of line).
                         ESC [ 1 K: erase from start of line to cursor.
                         ESC [ 2 K: erase whole line.
           L   IL        Insert the indicated # of blank lines.
           M   DL        Delete the indicated # of lines.
           P   DCH       Delete the indicated # of characters on current line.
           X   ECH       Erase the indicated # of characters on current line.
           a   HPR       Move cursor right the indicated # of columns.
           c   DA        Answer ESC [ ? 6 c: "I am a VT102".
           d   VPA       Move cursor to the indicated row, current column.
           e   VPR       Move cursor down the indicated # of rows.
           f   HVP       Move cursor to the indicated row, column.
           g   TBC       Without parameter: clear tab stop at current position.
                         ESC [ 3 g: delete all tab stops.
           h   SM        Set Mode (see below).
           l   RM        Reset Mode (see below).
           m   SGR       Set attributes (see below).
           n   DSR       Status report (see below).
           q   DECLL     Set keyboard LEDs.
                         ESC [ 0 q: clear all LEDs
                         ESC [ 1 q: set Scroll Lock LED
                         ESC [ 2 q: set Num Lock LED
                         ESC [ 3 q: set Caps Lock LED
           r   DECSTBM   Set scrolling region; parameters are top and bottom row.
           s   ?         Save cursor location.
           u   ?         Restore cursor location.
           `   HPA       Move cursor to indicated column in current row.
           ECMA-48 Set Graphics Rendition
           The  ECMA-48  SGR  sequence ESC [ parameters m sets display attributes.
           Several attributes can be set in the same sequence, separated by  semi-
           colons.   An empty parameter (between semicolons or string initiator or
           terminator) is interpreted as a zero.
           param   result
                   meta  flag  (ECMA-48  says "second alternate font").  The
                   toggle meta flag causes the high bit of a byte to be tog-
                   gled before the mapping table translation is done.
           21      set normal intensity (ECMA-48 says "doubly underlined")
           22      set normal intensity
           24      underline off
           25      blink off
           27      reverse video off
           30      set black foreground
           31      set red foreground
           32      set green foreground
           33      set brown foreground
           34      set blue foreground
           35      set magenta foreground
           36      set cyan foreground
           37      set white foreground
           38      set underscore on, set default foreground color
           39      set underscore off, set default foreground color
           40      set black background
           41      set red background
           42      set green background
           43      set brown background
           44      set blue background
           45      set magenta background
           46      set cyan background
           47      set white background
           49      set default background color
           ECMA-48 Mode Switches
           ESC [ 3 h
                  DECCRM (default off): Display control chars.
           ESC [ 4 h
                  DECIM (default off): Set insert mode.
           ESC [ 20 h
                  LF/NL  (default  off): Automatically follow echo of LF, VT or FF
                  with CR.
           ECMA-48 Status Report Commands
           ESC [ 5 n
                  Device status report (DSR): Answer is ESC [ 0 n (Terminal OK).
           ESC [ 6 n
                  Cursor position report (CPR): Answer is ESC [ y ; x R, where x,y
                  is the cursor location.
           DEC Private Mode (DECSET/DECRST) sequences
           These  are  not  described in ECMA-48.  We list the Set Mode sequences;
                  DECSCNM (default off): Set reverse-video mode.
           ESC [ ? 6 h
                  DECOM  (default off): When set, cursor addressing is relative to
                  the upper left corner of the scrolling region.
           ESC [ ? 7 h
                  DECAWM (default on): Set autowrap on.  In this mode,  a  graphic
                  character  emitted  after column 80 (or column 132 of DECCOLM is
                  on) forces a wrap to the beginning of the following line  first.
           ESC [ ? 8 h
                  DECARM (default on): Set keyboard autorepeat on.
           ESC [ ? 9 h
                  X10  Mouse  Reporting (default off): Set reporting mode to 1 (or
                  reset to 0)--see below.
           ESC [ ? 25 h
                  DECTECM (default on): Make cursor visible.
           ESC [ ? 1000 h
                  X11 Mouse Reporting (default off): Set reporting mode to  2  (or
                  reset to 0)--see below.
           Linux Console Private CSI Sequences
           The following sequences are neither ECMA-48 nor native VT102.  They are
           native to the Linux console driver.  Colors are in SGR parameters: 0  =
           black,  1 = red, 2 = green, 3 = brown, 4 = blue, 5 = magenta, 6 = cyan,
           7 = white.
           ESC [ 1 ; n ]       Set color n as the underline color
           ESC [ 2 ; n ]       Set color n as the dim color
           ESC [ 8 ]           Make the current color pair the default attributes.
           ESC [ 9 ; n ]       Set screen blank timeout to n minutes.
           ESC [ 10 ; n ]      Set bell frequency in Hz.
           ESC [ 11 ; n ]      Set bell duration in msec.
           ESC [ 12 ; n ]      Bring specified console to the front.
           ESC [ 13 ]          Unblank the screen.
           ESC [ 14 ; n ]      Set the VESA powerdown interval in minutes.
       Character sets
           The kernel knows about 4 translations of bytes into console-screen sym-
           bols.   The  four tables are: a) Latin1 -> PC, b) VT100 graphics -> PC,
           c) PC -> PC, d) user-defined.
           There are two character sets, called G0 and G1, and one of them is  the
           current  character set.  (Initially G0.)  Typing ^N causes G1 to become
           current, ^O causes G0 to become current.
           These variables G0 and G1 point at a  translation  table,  and  can  be
           of  the mapping is that if a symbol c is printed, the symbol s = map[c]
           is sent to the video memory.  The bitmap that corresponds to s is found
           in the character ROM, and can be changed using setfont(8).
       Mouse tracking
           The  mouse  tracking facility is intended to return xterm(1)-compatible
           mouse status reports.  Because the console driver has no  way  to  know
           the device or type of the mouse, these reports are returned in the con-
           sole input stream only when the  virtual  terminal  driver  receives  a
           mouse  update  ioctl.   These ioctls must be generated by a mouse-aware
           user-mode application such as the gpm(8) daemon.
           The mouse  tracking  escape  sequences  generated  by  xterm(1)  encode
           numeric  parameters  in  a single character as value+040.  For example,
           '!' is 1.  The screen coordinate system is 1-based.
           The X10 compatibility mode sends an escape  sequence  on  button  press
           encoding  the  location and the mouse button pressed.  It is enabled by
           sending ESC [ ? 9 h and disabled with ESC [ ? 9 l.   On  button  press,
           xterm(1)  sends  ESC [ M bxy (6 characters).  Here b is button-1, and x
           and y are the x and y coordinates of the  mouse  when  the  button  was
           pressed.  This is the same code the kernel also produces.
           Normal  tracking mode (not implemented in Linux 2.0.24) sends an escape
           sequence on both button press and  release.   Modifier  information  is
           also  sent.   It is enabled by sending ESC [ ? 1000 h and disabled with
           ESC [ ? 1000 l.  On button press or release, xterm(1)  sends  ESC  [  M
           bxy.   The  low two bits of b encode button information: 0=MB1 pressed,
           1=MB2 pressed, 2=MB3 pressed, 3=release.  The upper  bits  encode  what
           modifiers were down when the button was pressed and are added together:
           4=Shift, 8=Meta, 16=Control.  Again x and y are the x and y coordinates
           of the mouse event.  The upper left corner is (1,1).
       Comparisons with other terminals
           Many different terminal types are described, like the Linux console, as
           being "VT100-compatible".  Here  we  discuss  differences  between  the
           Linux  console  and  the  two  most important others, the DEC VT102 and
           Control-character handling
           The VT102 also recognized the following control characters:
           NUL (0x00) was ignored;
           ENQ (0x05) triggered an answerback message;
           DC1 (0x11, ^Q, XON) resumed transmission;
           DC3 (0x13, ^S, XOFF) caused VT100 to ignore (and stop transmitting) all
                  codes except XOFF and XON.
           ESC X       SOS   Start of string.
           ESC ^       PM    Privacy message (ended by ESC \)
           ESC \       ST    String terminator
           ESC * ...         Designate G2 character set
           ESC + ...         Designate G3 character set
           The program xterm(1) (in VT100 mode) recognizes ESC c, ESC # 8, ESC  >,
           ESC =, ESC D, ESC E, ESC H, ESC M, ESC N, ESC O, ESC P ... ESC \, ESC Z
           (it answers ESC [ ? 1 ; 2 c, "I am a VT100 with advanced video option")
           and  ESC  ^  ...  ESC  \ with the same meanings as indicated above.  It
           accepts ESC (, ESC ), ESC *,  ESC + followed by 0, A,  B  for  the  DEC
           special character and line drawing set, UK, and US-ASCII, respectively.
           The user can configure xterm(1) to respond  to  VT220-specific  control
           sequences, and it will identify itself as a VT52, VT100, and up depend-
           ing on the way it is configured and initialized.
           It accepts ESC ] (OSC) for the setting of certain resources.  In  addi-
           tion  to  the ECMA-48 string terminator (ST), xterm(1) accepts a BEL to
           terminate an OSC string.  These are a few of the OSC control  sequences
           recognized by xterm(1):
           ESC ] 0 ; txt ST        Set icon name and window title to txt.
           ESC ] 1 ; txt ST        Set icon name to txt.
           ESC ] 2 ; txt ST        Set window title to txt.
           ESC ] 4 ; num; txt ST   Set ANSI color num to txt.
           ESC ] 10 ; txt ST       Set dynamic text color to txt.
           ESC ] 4 6 ; name ST     Change log file to name (normally disabled
                                   by a compile-time option)
           ESC ] 5 0 ; fn ST       Set font to fn.
           It recognizes the following with slightly modified meaning (saving more
           state, behaving closer to VT100/VT220):
           ESC 7  DECSC   Save cursor
           ESC 8  DECRC   Restore cursor
           It also recognizes
           ESC F          Cursor to lower left corner of screen (if enabled by
                          xterm(1)'s hpLowerleftBugCompat resource)
           ESC l          Memory lock (per HP terminals).
                          Locks memory above the cursor.
           ESC m          Memory unlock (per HP terminals).
           ESC n   LS2    Invoke the G2 character set.
           ESC o   LS3    Invoke the G3 character set.
           ESC |   LS3R   Invoke the G3 character set as GR.
           ESC }   LS2R   Invoke the G2 character set as GR.
           ESC ~   LS1R   Invoke the G1 character set as GR.
           It also recognizes ESC % and provides a more complete UTF-8 implementa-
           tion than Linux console.
           The xterm(1) program recognizes all of the DEC Private  Mode  sequences
           listed  above,  but none of the Linux private-mode sequences.  For dis-
           cussion of xterm(1)'s own private-mode sequences, refer  to  the  Xterm
           Control Sequences document by Edward Moy, Stephen Gildea, and Thomas E.
           Dickey available with the X distribution.  That document, though terse,
           is much longer than this manual page.  For a chronological overview,
           details changes to xterm.
           The vttest program
           demonstrates many of these control sequences.  The xterm(1) source dis-
           tribution also contains sample scripts which exercise other features.


           ESC 8 (DECRC) is not able to restore the character set changed with ESC


           In  2.0.23,  CSI  is  broken,  and  NUL  is  not  ignored inside escape
           Some  older  kernel  versions  (after  2.0)  interpret  8-bit   control
           sequences.   These  "C1  controls"  use  codes  between  128 and 159 to
           replace ESC [, ESC ] and similar two-byte control sequence  initiators.
           There  are  fragments  of  that in modern kernels (either overlooked or
           broken by changes to support UTF-8), but the implementation  is  incom-
           plete and should be regarded as unreliable.
           Linux  "private  mode" sequences do not follow the rules in ECMA-48 for
           private mode control sequences.  In particular, those ending with ]  do
           not  use  a  standard  terminating  character.   The  OSC (set palette)
           sequence is a greater problem, since xterm(1) may interpret this  as  a
           control  sequence  which requires a string terminator (ST).  Unlike the
           setterm(1) sequences which will be ignored (since they are invalid con-
           trol sequences), the palette sequence will make xterm(1) appear to hang
           (though pressing the return-key will fix that).  To accommodate  appli-
           cations  which  have been hardcoded to use Linux control sequences, set
           the xterm(1) resource brokenLinuxOSC to true.
           An older version of this document implied  that  Linux  recognizes  the
           ECMA-48 control sequence for invisible text.  It is ignored.


           console(4), console_ioctl(4), charsets(7)

    Linux 2012-08-05 CONSOLE_CODES(4)


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