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".
From the MS-DOS prompt command, the escape character can be specified as $e, e.g. prompt $e[44m;... would specify a blue background as part of the prompt. In most modern programming languages it can be specified as "\x1B" (Perl also offers the equivalent "\e"), in Java it can be specified as "\u001B", and in QBasic or GWBASIC, it can be specified as CHR$(27) or CHR$(&H1B).
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.
| Code | Effect |
|---|---|
| CSI n A | 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 | 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 | 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 | 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 ; m f | Moves the cursor to row n, column m. If n is not given, 1 is used. |
| CSI n G | Moves the cursor to column n. |
| CSI n ; m H | Moves the cursor to row n, column m. If n is not given, 1 is used. |
| CSI = n h | Set screen mode. (MS-DOS ANSI.SYS) |
| CSI n J | Clears part of the screen. If n is zero, 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. (Moves cursor to upper left on MS-DOS ANSI.SYS) |
| CSI n K | Erases part of the line. If n is zero, 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. |
| CSI = n l | Reset screen mode on MS-DOS ANSI.SYS. |
| CSI n [;k] m | Sets graphics parameters. After CSI can be one or more parameters separated with ;. |
| CSI code ; param [ ; param ] p | Redefines a key. |
| CSI 6 n | 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 s | Saves the cursor position. |
| CSI u | 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 |
| Code | Effect |
|---|---|
| 0 | All attributes off |
| 1 | Bold |
| 2 | Faint (not widely supported) |
| 3 | Italic (not widely supported) |
| 4 | Underlined (not widely supported) |
| 5 | Blink |
| 6 | Rapid blink (MS-DOS ANSI.SYS) |
| 7 | Reverse video |
| 8 | Concealed (Not widely supported) |
| 9 | Crossed out (Not widely supported) |
| 22 | Normal intensity - not bold and not faint |
| 24 | Not underlined |
| 30 | Black foreground |
| 31 | Red foreground |
| 32 | Green foreground |
| 33 | Yellow foreground |
| 34 | Blue foreground |
| 35 | Magenta foreground |
| 36 | Cyan foreground |
| 37 | White foreground |
| 39 | Default foreground |
| 40 | Black background |
| 41 | Red background |
| 42 | Green background |
| 43 | Yellow background |
| 44 | Blue background |
| 45 | Magenta background |
| 46 | Cyan background |
| 47 | White background |
| 48 | Subscript (nonstandard) |
| 49 | Default background (or superscript - nonstandard) |
[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 locates the cursor to the y,x position 0,0 (upper left corner).
CSI 32 m - This makes text green. 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. This can also be accomplished with CSI 32 ; 1 m
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
