ANSI escape code
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ANSI escape codes are used to control text formatting and other output options on text terminals that are based on the ANSI X3.64 standard, which is also known as ECMA-48 and ISO/IEC 6429. All these escape sequences start with the characters ESC (ASCII 27d / 1Bh / 033o ) and [ (left bracket). This sequence is called CSI for "Control Sequence Introducer".
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[edit] Support
Support is built in on Linux. Windows 95, Windows 98 and DOS systems need a device driver for the ANSI codes - the de facto standard being ANSI.SYS, but others are used as well. Console windows in Windows versions based on NT (NT4, 2000 Professional, 2000 Server, XP, Server 2003, Vista, Server "Longhorn") do not natively support ANSI Escape sequences, though some support is possible. By adding the following line to the CONFIG.NT file located in the Windows System32 directory, ANSI output from 16-bit legacy programs executing under the NTVDM will be interpreted:
DEVICE=ANSI.SYS
Some support is also offered through alternate command processors such as JP Software's 4NT.
In other words, 32-bit character-mode windows applications can not write ANSI escape sequences to the console, but must interpret their actions and call the native Console API intrinsic to accomplish the proper result. Note that the window's Console API does have some restrictions regarding blink, underline and reverse VGA attributes. In exchange for blink, the screen allows for bright background colors. No access from user-mode is given to set the underline registers. The following attribute bits for SetConsoleTextAttribute() have no function even though they are listed:
COMMON_LVB_REVERSE_VIDEO COMMON_LVB_UNDERSCORE
Reverse can be emulated in one's code without much difficulty.
If ANSI.SYS is loaded in MS-DOS, the escape character can be specified as $e in the prompt command, e.g. prompt $e[44m;... would specify a blue background as part of the prompt. In most modern programming languages it can be specified as "\x1B" (Perl and Ruby also offer the equivalent "\e"), in Java it can be specified as "\u001B", and in QBasic or GWBASIC, it can be specified as CHR$(27) or CHR$(&H1B).
Note: most systems only support a subset of the SGR (Select Graphic Rendition) codes.
The control sequence introducer is CSI (control sequence introducer: 155d / 9Bh / 233o ) in ISO 8859. For 7-bit ASCII and other 8-bit code pages which use the 0x80 - 0x9F control character range for other purposes, it is ESC (escape: 27d / 1Bh / 033o ) and [ (square bracket: 91d / 5Bh / 133o). The ESC [ two character sequence is more often utilized than CSI single character sequence.
[edit] Codes
| Code | Name | Effect |
|---|---|---|
| CSI n A | CUU | Moves the cursor up n rows. If the cursor is already at the top of the screen, this has no effect. If n is not given, 1 is used. |
| CSI n B | CUD | Moves the cursor down n rows. If the cursor is already at the bottom of the screen, this has no effect. If n is not given, 1 is used. |
| CSI n C | CUF | Moves the cursor right n columns. If the cursor is already at the edge of the screen, this has no effect. If n is not given, 1 is used. |
| CSI n D | CUB | Moves the cursor left n columns. If the cursor is already at the edge of the screen, this has no effect. If n is not given, 1 is used. |
| CSI n E | CNL | Moves cursor to beginning of next line(s). If n is not given, 1 is used. |
| CSI n F | CPL | Moves cursor to beginning of previous line(s). If n is not given, 1 is used. |
| CSI n G | CHA | Moves the cursor to column n. |
| CSI n ; m H | CUP | Moves the cursor to row n, column m. If n or m is not given, 1 is used. Note: upper-left is one-based CSI 1;1H, not zero-based. A sequence such as CSI ;5H is a synonym for CSI 1;5H as well as CSI 17;H is the same as CSI 17H and CSI 17;1H |
| CSI n J | ED | Clears part of the screen. If n is zero (or missing), clear from cursor to end of screen. If n is one, clear from cursor to beginning of the screen. If n is two, clear entire screen (and moves cursor to upper left on MS-DOS ANSI.SYS). |
| CSI n K | EL | Erases part of the line. If n is zero (or missing), clear from cursor to the end of the line. If n is one, clear from cursor to beginning of the line. If n is two, clear entire line. Cursor position does not change. |
| CSI n S | SU | Scroll whole page up by the given number of lines. New lines are added at the bottom. Defaults to one line when n is missing. (not ANSI.SYS) |
| CSI n T | SD | Scroll whole page down by the given number of lines. New lines are added at the top. Defaults to one line when n is missing. (not ANSI.SYS) |
| CSI n ; m f | HVP | Moves the cursor to row n, column m. If n is not given, 1 is used. Same as CUP |
| CSI = n h | - | Set screen mode. (MS-DOS ANSI.SYS) |
| CSI = n l | - | Reset screen mode on MS-DOS ANSI.SYS. |
| CSI n [;k] m | SGR | Sets SGR (Select Graphic Rendition) parameters. After CSI can be zero or more parameters separated with ;. With no parameters, CSI m is treated as CSI 0 m (reset / normal), which is typical of most of the ANSI codes. |
| CSI 6 n | DSR | Reports the cursor position to the application as (as though typed at the keyboard) ESC[n;mR, where n is the row and m is the column. (May not work on MS-DOS ANSI.SYS) |
| CSI code ; param [ ; param ] p | - | Redefines a key. (MS-DOS ANSI.SYS) |
| CSI s | SCP | Saves the cursor position. |
| CSI u | RCP | Restores the cursor position. |
| Code | Effect |
|---|---|
| 0 | 40 × 25 mono |
| 1 | 40 × 25 color |
| 2 | 80 × 25 mono |
| 3 | 80 × 25 color |
| 4 | 320 × 200 color |
| 5 | 320 × 200 mono |
| 6 | 640 × 200 mono |
| 7 | Wrap at end of line |
| 13 | 320 x 200 color (graphics) |
| 14 | 640 x 200 color (16-color graphics) |
| 15 | 640 x 350 monochrome (2-color graphics) |
| 16 | 640x 350 color (16-color graphics) |
| 17 | 640 x 480 monochrome (2-color graphics) |
| 18 | 640 x 480 color (16-color graphics) |
| 19 | 320 x 200 color (256-color graphics) |
| Code | Effect | Note |
|---|---|---|
| 0 | Reset / Normal | all attributes off |
| 1 | Intensity: Bold | |
| 2 | Intensity: Faint | not widely supported |
| 3 | Italic: on | not widely supported |
| 4 | Underline: Single | not widely supported |
| 5 | Blink: Slow | less than 150 per minute |
| 6 | Blink: Rapid | MS-DOS ANSI.SYS; 150 per minute or more |
| 7 | Image: Negative | inverse or reverse; swap foreground and background |
| 8 | Conceal | not widely supported |
| 9 | Strikethrough: on | not widely supported |
| 10 | Font: Primary (default) | not widely supported |
| 11 | Font: First Alternative | not widely supported |
| 12 | Font: Second Alternative | not widely supported |
| 13 | Font: Third Alternative | not widely supported |
| 14 | Font: Fourth Alternative | not widely supported |
| 15 | Font: Fifth Alternative | not widely supported |
| 16 | Font: Sixth Alternative | not widely supported |
| 17 | Font: Seventh Alternative | not widely supported |
| 18 | Font: Eighth Alternative | not widely supported |
| 19 | Font: Ninth Alternative | not widely supported |
| 20 | Font: Fraktur (Gothic) | not widely supported |
| 21 | Underline: Double | |
| 22 | Intensity: Normal | not bold and not faint |
| 23 | Italic: off | |
| 24 | Underline: None | |
| 25 | Blink: off | |
| 26 | (reserved) | reserved for CCITT recommendation T.61 for proportional spacing |
| 27 | Image: Positive | |
| 28 | Reveal | conceal off |
| 29 | Strikethrough: off | |
| 30 | Foreground: Black | |
| 31 | Foreground: Red | |
| 32 | Foreground: Green | |
| 33 | Foreground: Yellow | or brown (sometimes orange at low-intensity) |
| 34 | Foreground: Blue | |
| 35 | Foreground: Magenta | |
| 36 | Foreground: Cyan | |
| 37 | Foreground: White | bright grey |
| 38 | (reserved) | reserved for ISO 8613-6 (CCITT recommendation T.416) for setting foreground color |
| 39 | Foreground: default | |
| 40 | Background: Black | |
| 41 | Background: Red | |
| 42 | Background: Green | |
| 43 | Background: Yellow | or brown (sometimes orange at low-intensity) |
| 44 | Background: Blue | |
| 45 | Background: Magenta | |
| 46 | Background: Cyan | |
| 47 | Background: White | bright grey |
| 48 | (reserved) | reserved for ISO 8613-6 (CCITT recommendation T.416) for setting background color |
| 48 | Subscript | nonstandard |
| 49 | Background: default | |
| 49 | Superscript | nonstandard |
| 50 | (reserved) | reserved for cancelling 26 proportional spacing |
| 51 | framed | |
| 52 | encircled | |
| 53 | overlined | |
| 54 | not framed, not encircled | |
| 55 | not overlined | |
| 56 | (reserved) | reserved for future standardization |
| 57 | (reserved) | reserved for future standardization |
| 58 | (reserved) | reserved for future standardization |
| 59 | (reserved) | reserved for future standardization |
| 60 | ideogram underline or right side line | |
| 61 | ideogram double underline or double right side line | |
| 62 | ideogram overline or left side line | |
| 63 | ideogram double overline or double left side line | |
| 64 | ideogram stress marking | |
| 90 | Foreground: Bright Black | dark grey |
| 91 | Foreground: Bright Red | |
| 92 | Foreground: Bright Green | |
| 93 | Foreground: Bright Yellow | |
| 94 | Foreground: Bright Blue | |
| 95 | Foreground: Bright Magenta | |
| 96 | Foreground: Bright Cyan | |
| 97 | Foreground: Bright White | |
| 100 | Background: Bright Black | dark grey |
| 101 | Background: Bright Red | |
| 102 | Background: Bright Green | |
| 103 | Background: Bright Yellow | |
| 104 | Background: Bright Blue | |
| 105 | Background: Bright Magenta | |
| 106 | Background: Bright Cyan | |
| 107 | Background: Bright White |
[edit] Examples
CSI 0 ; 6 8 ; "DIR" ; 13 p - This re-assigns the key F10 to send to the keyboard buffer the string "DIR" and ENTER, which in the DOS command line would display the contents of the current directory. (MS-DOS ANSI.SYS only)
CSI 2 J - This clears the screen and, on some systems, locates the cursor to the y,x position 1,1 (upper left corner).
CSI 32 m - This makes text green. On MS-DOS, normally the green would be dark, dull green, so you may wish to enable Bold with the code CSI 1 m which would make it bright green, or combined as CSI 32 ; 1 m. MS-DOS ANSI.SYS uses the Bold state to make the character Bright; also the Blink state can be set (via INT 10, AX 1003h, BL 00h) to render the Background in the Bright mode. MS-DOS ANSI.SYS does not support SGR codes 90-97 and 100-107 directly.
CSI s - This saves the cursor position. Using the code CSI u will restore it to the position. Say the current cursor position is 7(y) and 10(x). The code CSI s will save those two numbers. Now you can move to a different cursor position, such as 20(y) and 3(x), using the code CSI 20 ; 3 H or CSI 20 ; 3 f. Now if you use the code CSI u the cursor position will return to 7(y) and 10(x). Some terminals require the DEC sequences ESC 7 / ESC 8 instead.
[edit] See also
[edit] External links
- Standard ECMA-48: Control Functions for Coded Character Sets 5th edition (June 1991)
- ANSI Escape Code Usage Example
- ANSI.SYS -- ansi terminal emulation escape sequences
- ANSI/VT100 Terminal Control Escape Sequences
- ANSI CODES
- Xterm / Escape Sequences
- terminals that are vaguely compliant with ECMA-48 and friends.
