Notes › _DIFFUSION

Bash tips: Colors and formatting (ANSI/VT100 Control sequences)

The ANSI/VT100 terminals and terminal emulators are not just able to display black and white text ; they can display colors and formatted texts thanks to escape sequences. Those sequences are composed of the Escape character (often represented by “^[” or “<Esc>”) followed by some other characters: “<Esc>[FormatCodem”.

In Bash, the <Esc> character can be obtained with the following syntaxes:

• \e
• \033
• \x1B

Examples:

Code (Bash)	Preview
echo -e “\e[31mHello World\e[0m”
echo -e “\033[31mHello\e[0m World”

NOTE¹: The -e option of the echo command enable the parsing of the escape sequences.

NOTE²: The “\e[0m” sequence removes all attributes (formatting and colors). It can be a good idea to add it at the end of each colored text. ;)

NOTE³: The examples in this page are in Bash but the ANSI/VT100 escape sequences can be used in every programming languages.

Formatting

Here are the most commonly supported control sequences for formatting text. Their support depends on the used terminal (see the compatibility list).

Set

Code	Description	Example	Preview
1	Bold/Bright	echo -e “Normal \e[1mBold”
2	Dim	echo -e “Normal \e[2mDim”
4	Underlined	echo -e “Normal \e[4mUnderlined”
5	Blink 1)	echo -e “Normal \e[5mBlink”
7	Reverse (invert the foreground and background colors)	echo -e “Normal \e[7minverted”
8	Hidden (useful for passwords)	echo -e “Normal \e[8mHidden”

Reset

Code	Description	Example	Preview
0	Reset all attributes	echo -e “\e[0mNormal Text”
21	Reset bold/bright	echo -e “Normal \e[1mBold \e[21mNormal”
22	Reset dim	echo -e “Normal \e[2mDim \e[22mNormal”
24	Reset underlined	echo -e “Normal \e[4mUnderlined \e[24mNormal”
25	Reset blink	echo -e “Normal \e[5mBlink \e[25mNormal”
27	Reset reverse	echo -e “Normal \e[7minverted \e[27mNormal”
28	Reset hidden	echo -e “Normal \e[8mHidden \e[28mNormal”

8/16 Colors

The following colors works with most terminals and terminals emulators 2), see the compatibility list for more informations.

NOTE: The colors can vary depending of the terminal configuration.

Foreground (text)

Code	Color	Example	Preview
39	Default foreground color	echo -e “Default \e[39mDefault”
30	Black	echo -e “Default \e[30mBlack”
31	Red	echo -e “Default \e[31mRed”
32	Green	echo -e “Default \e[32mGreen”
33	Yellow	echo -e “Default \e[33mYellow”
34	Blue	echo -e “Default \e[34mBlue”
35	Magenta	echo -e “Default \e[35mMagenta”
36	Cyan	echo -e “Default \e[36mCyan”
37	Light gray	echo -e “Default \e[37mLight gray”
90	Dark gray	echo -e “Default \e[90mDark gray”
91	Light red	echo -e “Default \e[91mLight red”
92	Light green	echo -e “Default \e[92mLight green”
93	Light yellow	echo -e “Default \e[93mLight yellow”
94	Light blue	echo -e “Default \e[94mLight blue”
95	Light magenta	echo -e “Default \e[95mLight magenta”
96	Light cyan	echo -e “Default \e[96mLight cyan”
97	White	echo -e “Default \e[97mWhite”

Background

Code	Color	Example	Preview
49	Default background color	echo -e “Default \e[49mDefault”
40	Black	echo -e “Default \e[40mBlack”
41	Red	echo -e “Default \e[41mRed”
42	Green	echo -e “Default \e[42mGreen”
43	Yellow	echo -e “Default \e[43mYellow”
44	Blue	echo -e “Default \e[44mBlue”
45	Magenta	echo -e “Default \e[45mMagenta”
46	Cyan	echo -e “Default \e[46mCyan”
47	Light gray	echo -e “Default \e[47mLight gray”
100	Dark gray	echo -e “Default \e[100mDark gray”
101	Light red	echo -e “Default \e[101mLight red”
102	Light green	echo -e “Default \e[102mLight green”
103	Light yellow	echo -e “Default \e[103mLight yellow”
104	Light blue	echo -e “Default \e[104mLight blue”
105	Light magenta	echo -e “Default \e[105mLight magenta”
106	Light cyan	echo -e “Default \e[106mLight cyan”
107	White	echo -e “Default \e[107mWhite”

88/256 Colors

Some terminals (see the compatibility list) can support 88 or 256 colors. Here are the control sequences that permit you to use them.

NOTE¹: The colors number 256 is only supported by vte (GNOME Terminal, XFCE4 Terminal, Nautilus Terminal, Terminator,…).

NOTE²: The 88-colors terminals (like rxvt) does not have the same color map that the 256-colors terminals. For showing the 88-colors terminals color map, run the “256-colors.sh” script in a 88-colors terminal.

Foreground (text)

For using one of the 256 colors on the foreground (text color), the control sequence is “<Esc>[38;5;ColorNumberm” where ColorNumber is one of the following colors:

Examples:

Code (Bash)	Preview
echo -e “\e[38;5;82mHello \e[38;5;198mWorld”
for i in {16..21} {21..16} ; do echo -en “\e[38;5;${i}m#\e[0m” ; done ; echo

Background

For using one of the 256 colors on the background, the control sequence is “<Esc>[48;5;ColorNumberm” where ColorNumber is one of the following colors:

Examples:

Code (Bash)	Preview
echo -e “\e[40;38;5;82m Hello \e[30;48;5;82m World \e[0m”
for i in {16..21} {21..16} ; do echo -en “\e[48;5;${i}m \e[0m” ; done ; echo

Attributes combination

Terminals allow attribute combinations. The attributes must be separated by a semicolon (“;”).

Examples:

Description	Code (Bash)	Preview
Bold + Underlined	echo -e “\e[1;4mBold and Underlined”
Bold + Red forground + Green background	echo -e “\e[1;31;42m Yes it is awful \e[0m”

Terminals compatibility

Terminal	Formatting						Colors				Comment
Bold	Dim	Underlined	Blink	invert	Hidden	8	16	88	256
aTerm	ok	-	ok	-	ok	-	ok	~	-	-	Lighter background instead of blink.
Eterm	~	-	ok	-	ok	-	ok	~	-	ok	Lighter color instead of Bold. Lighter background instead of blink. Can overline a text with the “^[[6m” sequence.
GNOME Terminal	ok	ok	ok	ok	ok	ok	ok	ok	-	ok	Strikeout with the “^[[9m” sequence.
Guake	ok	ok	ok	ok	ok	ok	ok	ok	-	ok	Strikeout with the “^[[9m” sequence.
Konsole	ok	-	ok	ok	ok	-	ok	ok	-	ok
Nautilus Terminal	ok	ok	ok	ok	ok	ok	ok	ok	-	ok	Strikeout with the “^[[9m” sequence.
rxvt	ok	-	ok	~	ok	-	ok	ok	ok	-	If the background is not set to the default color, Blink make it lighter instead of blinking. Support of italic text with the “^[[3m” sequence.
Terminator	ok	ok	ok	-	ok	ok	ok	ok	-	ok	Strikeout with the “^[[9m” sequence.
Tilda	ok	-	ok	ok	ok	-	ok	ok	-	-	Underline instead of Dim. Convert 256-colors in 16-colors.
XFCE4 Terminal	ok	ok	ok	ok	ok	ok	ok	ok	-	ok	Strikeout with the “^[[9m” sequence.
XTerm	ok	-	ok	ok	ok	ok	ok	ok	-	ok
xvt	ok	-	ok	-	ok	-	-	-	-	-
Linux TTY	ok	-	-	-	ok	-	ok	~	-	-	Specials colors instead of Dim and Underlined. Lighter background instead of Blink, Bug with 88/256 colors.
VTE Terminal 3)	ok	ok	ok	ok	ok	ok	ok	ok	-	ok	Strikeout with the “^[[9m” sequence.

Notations used in the table:

• “ok”: Supported by the terminal.
• “~”: Supported in a special way by the terminal.
• “-”: Not supported at all by the terminal.

Demonstration programs

Colors and formatting (16 colors)

The following shell script displays a lot of possible combination of the attributes (but not all, because it uses only one formatting attribute at a time).

colors_and_formatting.sh

#!/bin/bash  

This program is free software. It comes without any warranty, to

the extent permitted by applicable law. You can redistribute it

and/or modify it under the terms of the Do What The Fuck You Want

To Public License, Version 2, as published by Sam Hocevar. See

http://sam.zoy.org/wtfpl/COPYING for more details.

  #Background for clbg in {40..47} {100..107} 49 ; do #Foreground for clfg in {30..37} {90..97} 39 ; do #Formatting for attr in 0 1 2 4 5 7 ; do #Print the result echo -en “\e[${attr};${clbg};${clfg}m ^[${attr};${clbg};${clfg}m \e[0m” done echo #Newline done done   exit 0

256 colors

The following script display the 256 colors available on some terminals and terminals emulators like XTerm and GNOME Terminal.

256-colors.sh