# ANSI escape code

(Redirected from ISO/IEC 6429)

In computing, ANSI escape codes (or escape sequences) are a method using in-band signaling to control the formatting, color, and other output options on video text terminals. To encode this formatting information, certain sequences of bytes are embedded into the text, which the terminal looks for and interprets as commands, not as character codes.

ANSI codes were introduced in the 1970s and became widespread in the minicomputer/mainframe market by the early 1980s. They were used by the nascent bulletin board system market to offer improved displays compared to earlier systems lacking cursor movement, leading to even more widespread use.

Although hardware text terminals have become increasingly rare in the 21st century, the relevance of the ANSI standard persists because most terminal emulators interpret at least some of the ANSI escape sequences in the output text. One notable exception was the Win32 console component of Microsoft Windows before Windows 10 update TH2.[1]

## History

Almost all manufacturers of video terminals added vendor-specific escape sequences to perform operations such as placing the cursor at arbitrary positions on the screen. One example is the VT52 terminal, which allowed the cursor to be placed at an x,y location on the screen by sending the `ESC` character, a `y` character, and then two characters representing with numerical values equal to the x,y location plus 32 (thus starting at the ASCII space character and avoiding the control characters).

As these sequences were different for different platforms, elaborate libraries such as termcap had to be created so programs could use the same API to work with any terminal. Most of these systems required sending numbers (such as row and column) as the binary values of the characters; for some programming languages, and for systems that did not use ASCII internally, it was often difficult or impossible to turn a number into the correct character.

The ANSI standard attempted to address these problems by making a command set that all terminals would use and requiring all numeric information to be transmitted as ASCII numbers. The first standard in the series was ECMA-48, adopted in 1976. It was a continuation of a series of character coding standards, the first one being ECMA-6 from 1965, a 7-bit standard from which ISO 646 originates. The name "ANSI escape sequence" dates from 1979 when ANSI adopted ANSI X3.64. The ANSI X3L2 committee collaborated with the ECMA committee TC 1 to produce nearly identical standards. These two standards were merged into an international standard, ISO 6429.[2] In 1994, ANSI withdrew its standard in favor of the international standard.

The first popular video terminal to support these sequences was the Digital VT100, introduced in 1978.[3] This model was very successful in the market, which sparked a variety of VT100 clones, among the earliest and most popular of which was the much more affordable Zenith Z-19 in 1979.[4] Others included the Qume QVT-108, Televideo TVI-970, Wyse WY-99GT as well as optional "VT100" or "VT103" or "ANSI" modes with varying degrees of compatibility on many other brands. The popularity of these gradually led to more and more software (especially bulletin board systems) assuming the escape sequences worked, leading to almost all new terminals and emulator programs supporting them.

In 1981, ANSI X3.64 was adopted for use in the US government by FIPS publication 86. Later, the US government stopped duplicating industry standards, so FIPS pub. 86 was withdrawn.[5]

ECMA-48 has been updated several times and is currently at its 5th edition, from 1991. It is also adopted by ISO and IEC as standard ISO/IEC 6429.

## Platform support

The widespread use of ANSI by bulletin boards and online services led to almost universal platform support by the mid 1980s. In most cases this took the form of a terminal emulator (such as xterm on Unix or the OS X Terminal or ZTerm on MacOS and many communication programs for the IBM PC), although there was increasing support in the standard text output of many operating systems.

Unix and the AmigaOS all included some ANSI support in the OS, which led to widespread use of ANSI by programs running on those platforms. Unix-like operating systems could produce ANSI codes through libraries such as termcap and curses used by many pieces of software to update the display. These libraries are supposed to support non-ANSI terminals as well, but this is so rarely tested nowadays that they are unlikely to work.[citation needed] Many games and shell scripts (such as colored prompts) directly write the ANSI sequences and thus cannot be used on a terminal that does not interpret them.

AmigaOS not only interprets ANSI code sequences for text output to the screen, the AmigaOS printer driver also interprets them (with extensions proprietary to AmigaOS) and translates them into the codes required for the particular printer that is actually attached.[6]

In spite of its popularity, ANSI codes were not universally supported. Support was not built-in on the original "classic" Mac OS, while the Atari ST used the command system adapted from the VT52 with some expansions for color support.[7]

### Windows and DOS

MS-DOS 1.x did not support the ANSI or any other escape sequences. Only a few control characters (BEL, CR, LF, BS) were interpreted by the underlying BIOS, making it almost[8] impossible to do any kind of full-screen application. Any display effects had to be done with BIOS calls, which were notoriously slow, or by directly manipulating the IBM PC hardware.

DOS 2.0 introduced the ability to add a device driver for the ANSI escape sequences – the de facto standard being ANSI.SYS, but others like ANSI.COM,[9] NANSI.SYS[10] and ANSIPLUS.EXE are used as well (these are considerably faster as they bypass the BIOS). Slowness and the fact that it was not installed by default made software rarely take advantage of it; instead, applications continued to directly manipulate the hardware to get the text display needed.[citation needed] ANSI.SYS and similar drivers continued to work in Windows 9x up to Windows Me, and in NT-derived systems for 16-bit legacy programs executing under the NTVDM.

The Win32 console did not support ANSI escape sequences at all until Windows 10 "Threshold 2".[1] Some replacements or additions for the console window such as JP Software's TCC (formerly 4NT), Michael J. Mefford's ANSI.COM, Jason Hood's ANSICON[11] and Maximus5's ConEmu do interpret ANSI escape sequences printed by programs.

Some software internally interprets ANSI escape sequences in text being printed and translates them to calls to manipulate the color and cursor position in the command output window,[12] to make it easier to port software using ANSI to Windows.

## Sequence elements

Sequences have different length. All sequences start with the character `ESC` (ASCII decimal `27`/hex `0x1B`/octal `033`) followed by a second character in the range ASCII `64``95` (`@` to `_`/hex `0x40``0x5F`).[13]:5.3.a

In 8-bit environments, these two character sequences can be merged into single byte, using the `0x80``0x9F` control character range.[13]:5.3.b Devices that support just ASCII (7-bit bytes) recognize only the two-character sequence. The same is true for devices that support 8-bit bytes but use the `0x80``0x9F` control character range for other purposes. On terminals that use UTF-8 encoding, both forms take 2 bytes ( the Control Sequence Introducer (CSI) in UTF-8 is `0xC2`, `0x9B`)[discuss] but the `ESC[` sequence is clearer.

However, most of the sequences are more than two characters and start with the characters `ESC` and `[` (left bracket/`0x5B`). On 8-bit systems there is a single-character (`155`/`0x9B` /`0233`) as well, still the `ESC[` two-character sequence is more often used than the single-character alternative (for details see C0 and C1 control codes).[13]:5.4.a This sequence is called CSI for Control Sequence Introducer (or Control Sequence Initiator). The final character of these sequences is in the range ASCII `64``126` (`@` to `~`/hex `0x40``0x7E`).[13]:5.4 Sequences that begin with the escape character are named escape sequences. Sequences beginning with the CSI are named control sequences. A sequence may be both an escape sequence and a control sequence.

Though some encodings use multiple bytes per character, the following discussion is restricted to ASCII characters, and thus assumes a single byte for each character.

## Non-CSI codes

The following describe some of the control sequences that do not begin with the CSI sequence. Note that other C0 codes besides ESC — commonly BEL, BS, CR, LF, FF, TAB, VT, SO, and SI — may produce similar or identical effects to some control sequences when output.

Some non-CSI escape sequences (not a complete list)
Escape Sequence Single-Byte Equivalent Name Effect
ESC N 0x8e SS2 – Single Shift Two Select a single character from one of the alternate character sets. In xterm, SS2 selects the G2 character set, and SS3 selects the G3 character set.[14]
ESC O 0x8f SS3 – Single Shift Three
ESC P 0x90 DCS – Device Control String Controls a device. In xterm, uses of this sequence include defining User-Defined Keys, and requesting or setting Termcap/Terminfo data.[14]
ESC \ 0x9c ST – String Terminator Terminates strings in other controls (including APC, DCS, OSC, PM, and SOS).[13]:8.3.143
ESC ] 0x9d OSC – Operating System Command Starts a control string for the operating system to use. OSC sequences are similar to CSI sequences, but are not limited to integer arguments. In general, these control sequences are terminated by ST.[13]:8.3.89 In xterm, they may also be terminated by BEL.[14] For example, in xterm, the window title can be set by `OSC 0;this is the window title BEL`.
ESC X 0x98 SOS – Start of String Takes an argument of a string of text, terminated by ST. The uses for these string control sequences are defined by the application[13]:8.3.2,8.3.128 or privacy discipline.[13]:8.3.94 These functions are not implemented and the arguments are ignored by xterm.[14]
ESC ^ 0x9e PM – Privacy Message
ESC _ 0x9f APC – Application Program Command
ESC c   RIS – Reset to Initial State Resets the device to its original state. This may include (if applicable): reset graphic rendition, clear tabulation stops, reset to default font, and more.

Note: pressing special keys on the keyboard, as well as outputting many xterm CSI, DCS, or OSC sequences, often produces a CSI, DCS, or OSC sequence.

## CSI codes

The general structure of most ANSI escape sequences is `CSI [private mode character(s?)] n1 ; n2... [trailing intermediate character(s?)] letter`. The final byte, modified by private mode characters and trailing intermediate characters, specifies the command. The numbers are optional parameters. The default value used for omitted parameters varies with the command, but is usually `1` or `0`. If trailing parameters are omitted, the trailing semicolons may also be omitted.

The final byte is technically any character in the range `64``126` (hex `0x40``0x7E`, ASCII `@` to `~`), and may be modified with leading intermediate bytes in the range `32` to `47` (hex `0x20``0x2F`, ASCII `space` to `/`).

The colon (`58`, hex `0x3A`) is the only character not a part of the general sequence. It was left for future standardization, so any sequence containing it should be ignored.

Although multiple private mode characters or trailing intermediates are permitted, there are no such known usages.[citation needed]

If there are any leading private mode characters, the main body of the sequence could theoretically contain any order of characters in the range `48``63` (hex `0x30``0x3F`, ASCII `0` to `?`) instead of a well-formed semicolon-separated list of numbers,[citation needed] but all known terminals use the non-digit characters in this range as flags.[citation needed] Sequences are also private if the final byte is in the range `112``126` (hex `0x70``0x7E`, ASCII `p``~`).

Examples of private escape codes include the DECTCEM (DEC text cursor enable mode) shown below. It was first introduced for the VT-300 series of video terminals.

The behavior of the terminal is undefined in the case where a CSI sequence contains any character outside of the range `32` to `126` (hex `0x20``0x7E`, ASCII `space``~`).[dubious ] These illegal characters are either C0 control characters (the range `0``31`, hex `0x00``0x1F`), character `127` (hex `0x7F`, ASCII `DEL`), or high-ASCII characters (the range `128``255`, hex `0x80``0xFF`).

Possibilities for handling illegal characters in a CSI sequence include:

1. Assuming the end of the CSI sequence, ignoring it and treating further characters as data;[citation needed]

2. Ignoring this sequence including all future characters through the next character that would normally end a CSI sequence (anything in the range `64``126` (hex `0x40``0x7E`, ASCII`@``~`));[citation needed] or

3. Processing any control code as the terminal normally would outside of a CSI sequence before continuing to parse the rest of the sequence.[citation needed]

Some ANSI control codes (not a complete list)
Code Name Effect

CSI `n` A CUU – Cursor Up Moves the cursor ${\displaystyle n}$ (default `1`) cells in the given direction. If the cursor is already at the edge of the screen, this has no effect.

CSI `n` B CUD – Cursor Down

CSI `n` C CUF – Cursor Forward

CSI `n` D CUB – Cursor Back
CSI `n` E CNL – Cursor Next Line Moves cursor to beginning of the line ${\displaystyle n}$ (default `1`) lines down. (not ANSI.SYS)
CSI `n` F CPL – Cursor Previous Line Moves cursor to beginning of the line ${\displaystyle n}$ (default `1`) lines up. (not ANSI.SYS)
CSI `n` G CHA – Cursor Horizontal Absolute Moves the cursor to column ${\displaystyle n}$ (default `1`). (not ANSI.SYS)

CSI `n` ; `m` H CUP – Cursor Position Moves the cursor to row ${\displaystyle n}$, column ${\displaystyle m}$. The values are 1-based, and default to `1` (top left corner) if omitted. 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 – Erase in Display Clears part of the screen. If ${\displaystyle n}$ is `0` (or missing), clear from cursor to end of screen. If ${\displaystyle n}$ is `1`, clear from cursor to beginning of the screen. If ${\displaystyle n}$ is `2`, clear entire screen (and moves cursor to upper left on DOS ANSI.SYS). If ${\displaystyle n}$ is `3`, clear entire screen and delete all lines saved in the scrollback buffer (this feature was added for xterm and is supported by other terminal applications).

CSI `n` K EL – Erase in Line Erases part of the line. If ${\displaystyle n}$ is zero (or missing), clear from cursor to the end of the line. If ${\displaystyle n}$ is one, clear from cursor to beginning of the line. If ${\displaystyle n}$ is two, clear entire line. Cursor position does not change.

CSI `n` S SU – Scroll Up Scroll whole page up by ${\displaystyle n}$ (default `1`) lines. New lines are added at the bottom. (not ANSI.SYS)

CSI `n` T SD – Scroll Down Scroll whole page down by ${\displaystyle n}$ (default `1`) lines. New lines are added at the top. (not ANSI.SYS)

CSI `n` ; `m` f HVP – Horizontal and Vertical Position Moves the cursor to row ${\displaystyle n}$, column ${\displaystyle m}$. Both default to `1` if omitted. Same as CUP

CSI `n` m SGR – Select Graphic Rendition Sets SGR parameters, including text color. 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 escape sequences.

CSI 5i AUX Port On Enable aux serial port usually for local serial printer

CSI 4i AUX Port Off Disable aux serial port usually for local serial printer

CSI 6n DSR – Device Status Report Reports the cursor position (CPR) to the application as (as though typed at the keyboard) `ESC[n;mR`, where ${\displaystyle n}$ is the row and ${\displaystyle m}$ is the column.)

CSI s SCP – Save Cursor Position Saves the cursor position.

CSI u RCP – Restore Cursor Position Restores the cursor position.
CSI ?25l DECTCEM Hides the cursor. (Note: the trailing character is lowercase `L`.)
CSI ?25h DECTCEM Shows the cursor.
SGR (Select Graphic Rendition) parameters
Code Effect Note
0 Reset / Normal all attributes off
1 Bold or increased intensity
2 Faint (decreased intensity) Not widely supported.
3 Italic: on Not widely supported. Sometimes treated as inverse.
4 Underline: Single
5 Blink: Slow less than 150 per minute
6 Blink: Rapid MS-DOS ANSI.SYS; 150+ per minute; not widely supported
7 Image: Negative inverse or reverse; swap foreground and background (reverse video)
8 Conceal Not widely supported.
9 Crossed-out Characters legible, but marked for deletion. Not widely supported.
10 Primary(default) font
11–19 ${\displaystyle n}$-th alternate font Select the ${\displaystyle n}$-th alternate font (14 being the fourth alternate font, up to 19 being the 9th alternate font).
20 Fraktur hardly ever supported
21 Bold: off or Underline: Double Bold off not widely supported; double underline hardly ever supported.
22 Normal color or intensity Neither bold nor faint
23 Not italic, not Fraktur
24 Underline: None Not singly or doubly underlined
26 Reserved
27 Image: Positive
28 Reveal conceal off
29 Not crossed out
30–37 Set text color (foreground) `30` + ${\displaystyle n}$, where ${\displaystyle n}$ is from the color table below
38 Reserved for extended set foreground color typical supported next arguments are `5;n` where ${\displaystyle n}$ is color index (`0..255`) or `2;r;g;b` where ${\displaystyle r,g,b}$ are red, green and blue color channels (out of `255`)
39 Default text color (foreground) implementation defined (according to standard)
40–47 Set background color `40` + ${\displaystyle n}$, where ${\displaystyle n}$ is from the color table below
48 Reserved for extended set background color typical supported next arguments are `5;n` where ${\displaystyle n}$ is color index (`0..255`) or `2;r;g;b` where ${\displaystyle r,g,b}$ are red, green and blue color channels (out of `255`)
49 Default background color implementation defined (according to standard)
50 Reserved
51 Framed
52 Encircled
53 Overlined
54 Not framed or encircled
55 Not overlined
56–59 Reserved
60 ideogram underline or right side line hardly ever supported
61 ideogram double underline or double line on the right side hardly ever supported
62 ideogram overline or left side line hardly ever supported
63 ideogram double overline or double line on the left side hardly ever supported
64 ideogram stress marking hardly ever supported
65 ideogram attributes off hardly ever supported, reset the effects of all of `60``64`
90–97 Set foreground text color, high intensity aixterm (not in standard)
100–107 Set background color, high intensity aixterm (not in standard)

## Colors

The original specification only had 8 colors, and just gave them names. The SGR parameters 30-37 selected the foreground color, while 40-47 selected the background. Quite a few terminals implemented "bold" (SGR code 1) as a brighter color rather than a different font, thus providing 8 additional foreground colors. Usually you could not get these as background colors, though sometimes inverse video (SGR code 7) would allow that. Examples: to get black letters on white background use `ESC[30;47m`, to get red use `ESC[31m`, to get bright red use `ESC[31;1m`. To reset colors to their defaults, use `ESC[39;49m` (not supported on some terminals), or reset all attributes with `ESC[0m`.

Color table[15]
Foreground Code 30 31 32 33 34 35 36 37
Background Code 40 41 42 43 44 45 46 47
Normal Black Red Green Yellow Blue Magenta Cyan White
Bright Black Red Green Yellow Blue Magenta Cyan White

When hardware started using 8-bit DACs several pieces of software assigned 24-bit color numbers to these names. The chart below shows default RGB assignments for some common hardware and software.[citation needed]

VGA[16] CMD[17] Terminal.app PuTTY mIRC xterm X[18] 0, 0, 0 0, 0, 0 0, 0, 0 0, 0, 0 0, 0, 0 0, 0, 0 0, 0, 0 170, 0, 0 128, 0, 0 194, 54, 33 187, 0, 0 127, 0, 0 205, 0, 0 255, 0, 0 0, 170, 0 0, 128, 0 37, 188, 36 0, 187, 0 0, 147, 0 0, 205, 0 0, 255, 0 170, 85, 0[19] 128, 128, 0 173, 173, 39 187, 187, 0 252, 127, 0 205, 205, 0 255, 255, 0 0, 0, 170 0, 0, 128 73, 46, 225 0, 0, 187 0, 0, 127 0, 0, 238[20] 0, 0, 255 170, 0, 170 128, 0, 128 211, 56, 211 187, 0, 187 156, 0, 156 205, 0, 205 255, 0, 255 0, 170, 170 0, 128, 128 51, 187, 200 0, 187, 187 0, 147, 147 0, 205, 205 0, 255, 255 170, 170, 170 192, 192, 192 203, 204, 205 187, 187, 187 210, 210, 210 229, 229, 229 255, 255, 255 85, 85, 85 128, 128, 128 129, 131, 131 85, 85, 85 127, 127, 127 127, 127, 127 255, 85, 85 255, 0, 0 252,57,31 255, 85, 85 255, 0, 0 255, 0, 0 85, 255, 85 0, 255, 0 49, 231, 34 85, 255, 85 0, 252, 0 0, 255, 0 144, 238, 144 255, 255, 85 255, 255, 0 234, 236, 35 255, 255, 85 255, 255, 0 255, 255, 0 255, 255, 224 85, 85, 255 0, 0, 255 88, 51, 255 85, 85, 255 0, 0, 252 92, 92, 255[21] 173, 216, 230 255, 85, 255 255, 0, 255 249, 53, 248 255, 85, 255 255, 0, 255 255, 0, 255 85, 255, 255 0, 255, 255 20, 240, 240 85, 255, 255 0, 255, 255 0, 255, 255 224, 255, 255 255, 255, 255 255, 255, 255 233, 235, 235 255, 255, 255 255, 255, 255 255, 255, 255

As 256-color lookup tables became common on graphic cards, escape sequences were added to select from a pre-defined set of 256 colors:[citation needed]

```   `ESC[ … 38;5;<n> … m Select foreground color`
`ESC[ … 48;5;<n> … m Select background color`
`0x00-0x07:  standard colors (as in ESC [ 30–37 m)`
`0x08-0x0F:  high intensity colors (as in ESC [ 90–97 m)`
`0x10-0xE7:  6 × 6 × 6 cube (216 colors): 16 + 36 × r + 6 × g + b (0 ≤ r, g, b ≤ 5)`
`0xE8-0xFF:  grayscale from black to white in 24 steps`
```
256-color mode — foreground: ESC[38;5;#m   background: ESC[48;5;#m
Standard colors High-intensity colors
 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
216 colors
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87
88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123
124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159
160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195
196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231
Grayscale colors
 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255

As "true color" graphic cards with 16 to 24 bits of color became common, Xterm,[14] KDE's Konsole,[22] as well as all libvte based terminals[23] (including GNOME Terminal) support ISO-8613-3 24-bit foreground and background color setting[better source needed] Quoting one of the text-files in its source-tree:[24]

```   `ESC[ … 38;2;<r>;<g>;<b> … m Select RGB foreground color`
`ESC[ … 48;2;<r>;<g>;<b> … m Select RGB background color`
```

The ITU's "T.416 Information technology - Open Document Architecture (ODA) and interchange format: Character content architectures". which was adopted as ISO/IEC International Standard 8613-6 gives more detail:

```   `ESC[ … 38:2:<r>:<g>:<b>:<unused>:<CS tolerance>:<Color-Space: 0="CIELUV"; 1="CIELAB">m Select RGB foreground color`
`ESC[ … 48:2:<r>:<g>:<b>:<unused>:<CS tolerance>:<Color-Space: 0="CIELUV"; 1="CIELAB">m Select RGB background color`
```

Note that this uses the otherwise reserved ':' character to separate the sub-options which may have been a source of confusion for real-world implementations. It also documents using '3' as the second parameter to specify colors using a Cyan-Magenta-Yellow scheme and '4' for a Cyan-Magenta-Yellow-Black one, the latter using the position marked as "unused" in the above examples for the Black component.

Xterm allows also setting colors by X11 color names using[14]

```   `ESC]10;<foreground>BEL`
`ESC]11;<background>BEL`
```

where `<foreground>` and `<background>` are text, and BEL is the ASCII BEL character (code 7). The closing bracket instead of an opening bracket reveals that it belongs to the operating system control commands.

## Examples

`CSI 2 J` — This clears the screen and, on some devices, 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 sequence `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 0 ; 6 8 ; "DIR" ; 13 p` — This reassigns 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) This was sometimes used for ANSI bombs. This is a private-use code (as indicated by the letter p), using a non-standard extension to include a string-valued parameter. Following the letter of the standard would consider the sequence to end at the letter D.

`CSI s` — This saves the cursor position. Using the sequence `CSI u` will restore it to the position. Say the current cursor position is 7(y) and 10(x). The sequence `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 sequence `CSI 20 ; 3 H` or `CSI 20 ; 3 f`. Now if you use the sequence CSI u the cursor position will return to 7(y) and 10(x). Some terminals require the DEC sequences `ESC 7` / `ESC 8` instead which is more widely supported.

### Example of use in shell scripting

ANSI escape codes are often used in UNIX and UNIX-like terminals to provide syntax highlighting. For example, on compatible terminals, the following list command color-codes file and directory names by type.

`ls --color`

Users can employ escape codes in their scripts by including them as part of standard output or standard error. For example, the following GNU sed command embellishes the output of the make command by displaying lines containing words starting with "WARN" in reverse video and words starting with "ERR" in bright yellow on a dark red background (letter case is ignored). The representations of the codes are highlighted.[25]

```make 2>&1 | sed -e 's/.*\bWARN.*/\x1b[7m&\x1b[0m/i' -e 's/.*\bERR.*/\x1b[93;41 m&\x1b[0m/i'
```

The following Bash function flashes the terminal (by alternately sending reverse and normal video mode codes) until the user presses a key.[26]

```flasher () { while true; do printf \\e[?5h; sleep 0.1; printf \\e[?5l; read -s -n1 -t1 && break; done; }
```

This can be used to alert a programmer when a lengthy command terminates, such as with `make ; flasher` .[27]

```printf \\033c
```

This will reset the console, similar to the command `reset` on modern Linux systems; however it should work even on older Linux systems and on other (non-Linux) UNIX variants.

## Invalid and ambiguous sequences in use

• The Linux console uses `OSC P n rr gg bb` to change the palette, which, if hard-coded into an application, may hang other terminals. However, appending `ST` will be ignored by Linux and form a proper, ignorable sequence for other terminals.[citation needed]
• On the Linux console, certain function keys generate sequences of the form `CSI [ char`. The CSI sequence should terminate on the [.
• Old versions of Terminator generate `SS3 1; modifiers char` when F1–F4 are pressed with modifiers. The faulty behavior was copied from GNOME Terminal.[citation needed]
• xterm replies `CSI row ; column R` if asked for cursor position and `CSI 1 ; modifiers R` if the F3 key is pressed with modifiers, which collide in the case of row == 1. This can be avoided by using the ? private modifier, which will be reflected in the response.[clarification needed]
• many terminals prepend `ESC` to any character that is typed with the alt key down. This creates ambiguity for uppercase letters and symbols @[\]^_, which would form C1 codes.[clarification needed]
• Konsole generates `SS3 modifiers char` when F1–F4 are pressed with modifiers.[clarification needed]

## Notes

1. ^ a b Oisin Grehan (4 February 2016). "Windows 10 TH2 (v1511) Console Host Enhancements". Retrieved 10 February 2016.
2. ^ Historical version of ECMA-48
3. ^ Paul Williams (2006). "Digital's Video Terminals". VT100.net. Retrieved 17 August 2011.
4. ^ Heathkit Company (1979). "Heathkit Catalog 1979". Heathkit Company. Retrieved 4 November 2011.
5. ^ Withdrawn FIPS Listed by Number
6. ^ "Amiga Printer Command Definitions". Commodore. Retrieved 10 July 2013.
7. ^ "Using C-Kermit", p. 88.
8. ^ The screen display could be replaced by drawing the entire new screen's contents at the bottom, scrolling the previous screen up sufficiently to erase all the old text. The user would see the scrolling, and the hardware cursor would be left at the very bottom. Some early batch files achieved rudimentary "full screen" displays in this way.
9. ^ Michael Mefford (7 February 1989). "ANSI.com: Download It Here". PC Magazine. Retrieved 10 August 2011.
10. ^ Dan Kegel, Eric Auer (28 February 1999). "Nansi and NNansi – ANSI Drivers for MS-DOS". Dan Kegel's Web Hostel. Retrieved 10 August 2011.
11. ^ Jason Hood (2005). "Process ANSI escape sequences for Windows console programs". Jason Hood's Home page. Retrieved 9 May 2013.
12. ^ "colorama 0.2.5 :". Python Package Index. Retrieved 17 August 2013.
13. "Standard ECMA-48: Control Functions for Coded Character Sets" (Fifth ed.). Ecma International. June 1991.
14. "XTerm Control Sequences". invisible-island.net. 13 January 2014. Retrieved 13 April 2014.
15. ^ The names are standard, however the exact shade/hue/value of colors are not standardized and will depend on the device used to display them.
16. ^ Typical colors that are used when booting PCs and leaving them in text mode, which used a 16-entry color table. The colors are different in the EGA/VGA graphic modes.
17. ^ As of Windows XP
18. ^ Above color name from X11 rgb.txt color database, with "light" prefixed for the bright colors
19. ^ On terminals based on CGA compatible hardware, such as ANSI.SYS running on DOS, this normal intensity foreground color is rendered as Orange. CGA RGBI monitors contained hardware to modify the dark yellow color to an orange/brown color by reducing the green component. See this ansi art as an example.
20. ^ Changed from 0,0,205 in July 2004 "Patch #192 – 2004/7/12 – XFree86 4.4.99.9".
21. ^ Changed from 0,0,255 in July 2004 "Patch #192 – 2004/7/12 – XFree86 4.4.99.9".
22. ^ "color-spaces.pl (a copy of 256colors2.pl from xterm dated 11 July 1999)". KDE. 6 December 2006.
23. ^ "libvte's bug report and patches". GNOME Bugzilla. 4 April 2014. Retrieved 5 June 2016.
24. ^ "README.moreColors". KDE. 22 April 2010.
25. ^ "Chapter 9. System tips". debian.org.
26. ^ "VT100.net: Digital VT100 User Guide". Retrieved 19 January 2015.
27. ^ "bash – How to get a notification when my commands are done – Ask Different". Retrieved 19 January 2015.