L_color¶

Use the L_* variables for colored output.

Use L_RESET or L_COLORRESET to reset color to defaults.

Use L_color_detect to detect if the terminal is supposed to support colors.

The interface is not great. The ultimate goal was to not to use any subshells.

The L_color_detect function sets or clears the L_* variables related to colors.

The issue is that if you redirect the output, you have to call L_color_detect again for each file descriptor change.

Additionally, if you output to a different file descriptor, you have to call L_color_detect again each time changing the file descriptor.

Usually, colors are really used for logging output. Like the following:

The function L_color_detect is not even that costly. However, I do not enjoy the alternative of spawning a subshell.

exec {logfd}>&1
L_color_detect >&$logfd
echo "$L_GREEN""Hello world""$L_RESET" >&$logfd

Color and Style Variables¶

All variables listed in L_COLOR_VARIABLES are set by L_color_enable and cleared by L_color_disable/L_color_detect (when color is not supported).

Category	Variables	ANSI Code	Description
Reset	`L_RESET`, `L_COLORRESET`	`\E[m` / `\E[0m`	Reset all attributes
Text Styles
	`L_BOLD`, `L_BRIGHT`	`\E[1m`	Bold / increased intensity
	`L_DIM`, `L_FAINT`	`\E[2m`	Faint / decreased intensity
	`L_ITALIC`, `L_STANDOUT`	`\E[3m`	Italic
	`L_UNDERLINE`	`\E[4m`	Single underline
	`L_BLINK`	`\E[5m`	Slow blink
	`L_REVERSE`	`\E[7m`	Reverse video (swap fg/bg)
	`L_CONCEAL`, `L_HIDDEN`	`\E[8m`	Conceal / hidden
	`L_CROSSEDOUT`	`\E[9m`	Crossed out / strikethrough
Fonts
	`L_FONT0`–`L_FONT9`	`\E[10m`–`\E[19m`	Font selection (0=default, 1-9=alternatives)
	`L_FRAKTUR`	`\E[20m`	Fraktur (Gothic) font
	`L_DOUBLE_UNDERLINE`	`\E[21m`	Double underline
Style Resets
	`L_NODIM`	`\E[22m`	Reset dim/faint (turn off bold/dim)
	`L_NOSTANDOUT`	`\E[23m`	Reset italic/standout
	`L_NOUNDERLINE`	`\E[24m`	Reset underline
	`L_NOBLINK`	`\E[25m`	Reset blink
	`L_NOREVERSE`	`\E[27m`	Reset reverse
	`L_NOHIDDEN`, `L_REVEAL`	`\E[28m`	Reset conceal/hidden
	`L_NOCROSSEDOUT`	`\E[29m`	Reset crossed out
Foreground Colors (Standard)
	`L_BLACK`	`\E[30m`	Black
	`L_RED`	`\E[31m`	Red
	`L_GREEN`	`\E[32m`	Green
	`L_YELLOW`	`\E[33m`	Yellow
	`L_BLUE`	`\E[34m`	Blue
	`L_MAGENTA`	`\E[35m`	Magenta
	`L_CYAN`	`\E[36m`	Cyan
	`L_LIGHT_GRAY`	`\E[37m`	Light gray / white
	`L_DEFAULT`, `L_FOREGROUND_DEFAULT`	`\E[39m`	Default foreground
Foreground Colors (Bright/High-intensity)
	`L_DARK_GRAY`	`\E[90m`	Dark gray (bright black)
	`L_LIGHT_RED`	`\E[91m`	Light red
	`L_LIGHT_GREEN`	`\E[92m`	Light green
	`L_LIGHT_YELLOW`	`\E[93m`	Light yellow
	`L_LIGHT_BLUE`	`\E[94m`	Light blue
	`L_LIGHT_MAGENTA`	`\E[95m`	Light magenta
	`L_LIGHT_CYAN`	`\E[96m`	Light cyan
	`L_WHITE`	`\E[97m`	White (bright white)
Background Colors (Standard)
	`L_BG_BLACK`	`\E[40m`	Black background
	`L_BG_RED`	`\E[41m`	Red background
	`L_BG_GREEN`	`\E[42m`	Green background
	`L_BG_YELLOW`	`\E[43m`	Yellow background
	`L_BG_BLUE`	`\E[44m`	Blue background
	`L_BG_MAGENTA`	`\E[45m`	Magenta background
	`L_BG_CYAN`	`\E[46m`	Cyan background
	`L_BG_LIGHT_GRAY`	`\E[47m`	Light gray background
	`L_BG_DEFAULT`	`\E[49m`	Default background
Background Colors (Bright/High-intensity)
	`L_BG_DARK_GRAY`	`\E[100m`	Dark gray background
	`L_BG_LIGHT_RED`	`\E[101m`	Light red background
	`L_BG_LIGHT_GREEN`	`\E[102m`	Light green background
	`L_BG_LIGHT_YELLOW`	`\E[103m`	Light yellow background
	`L_BG_LIGHT_BLUE`	`\E[104m`	Light blue background
	`L_BG_LIGHT_MAGENTA`	`\E[105m`	Light magenta background
	`L_BG_LIGHT_CYAN`	`\E[106m`	Light cyan background
	`L_BG_WHITE`	`\E[107m`	White background
Special Effects
	`L_FRAMED`	`\E[51m`	Framed
	`L_ENCIRCLED`	`\E[52m`	Encircled
	`L_OVERLINED`	`\E[53m`	Overlined
	`L_NOENCIRCLED`, `L_NOFRAMED`	`\E[54m`	Not encircled / not framed
	`L_NOOVERLINED`	`\E[55m`	Not overlined

Constant ANSI Variables (Always Available)¶

These L_ANSI_* variables are always set to their escape sequences, regardless of color detection:

Variable	ANSI Code	Description
`L_ANSI_BOLD`, `L_ANSI_BRIGHT`	`\E[1m`	Bold
`L_ANSI_DIM`, `L_ANSI_FAINT`	`\E[2m`	Dim/Faint
`L_ANSI_STANDOUT`	`\E[3m`	Italic/Standout
`L_ANSI_UNDERLINE`	`\E[4m`	Underline
`L_ANSI_BLINK`	`\E[5m`	Blink
`L_ANSI_REVERSE`	`\E[7m`	Reverse
`L_ANSI_CONCEAL`, `L_ANSI_HIDDEN`	`\E[8m`	Conceal/Hidden
`L_ANSI_CROSSEDOUT`	`\E[9m`	Crossed out
`L_ANSI_FONT0`–`L_ANSI_FONT9`	`\E[10m`–`\E[19m`	Font selection
`L_ANSI_FRAKTUR`	`\E[20m`	Fraktur font
`L_ANSI_DOUBLE_UNDERLINE`	`\E[21m`	Double underline
`L_ANSI_NODIM`	`\E[22m`	Reset dim
`L_ANSI_NOSTANDOUT`	`\E[23m`	Reset italic
`L_ANSI_NOUNDERLINE`	`\E[24m`	Reset underline
`L_ANSI_NOBLINK`	`\E[25m`	Reset blink
`L_ANSI_NOREVERSE`	`\E[27m`	Reset reverse
`L_ANSI_NOHIDDEN`, `L_ANSI_REVEAL`	`\E[28m`	Reset conceal
`L_ANSI_NOCROSSEDOUT`	`\E[29m`	Reset crossed out
Background Colors (Standard)
`L_ANSI_BG_BLACK`	`\E[40m`	Black background
`L_ANSI_BG_RED`	`\E[41m`	Red background
`L_ANSI_BG_GREEN`	`\E[42m`	Green background
`L_ANSI_BG_YELLOW`	`\E[43m`	Yellow background
`L_ANSI_BG_BLUE`	`\E[44m`	Blue background
`L_ANSI_BG_MAGENTA`	`\E[45m`	Magenta background
`L_ANSI_BG_CYAN`	`\E[46m`	Cyan background
`L_ANSI_BG_LIGHT_GRAY`	`\E[47m`	Light gray background
`L_ANSI_BG_DEFAULT`	`\E[49m`	Default background
Background Colors (Bright/High-intensity)
`L_ANSI_BG_DARK_GRAY`	`\E[100m`	Dark gray background
`L_ANSI_BG_LIGHT_RED`	`\E[101m`	Light red background
`L_ANSI_BG_LIGHT_GREEN`	`\E[102m`	Light green background
`L_ANSI_BG_LIGHT_YELLOW`	`\E[103m`	Light yellow background
`L_ANSI_BG_LIGHT_BLUE`	`\E[104m`	Light blue background
`L_ANSI_BG_LIGHT_MAGENTA`	`\E[105m`	Light magenta background
`L_ANSI_BG_LIGHT_CYAN`	`\E[106m`	Light cyan background
`L_ANSI_BG_WHITE`	`\E[107m`	White background

API Reference¶

colors ¶

Variables storing xterm ANSI escape sequences for colors.

Variables with L_ANSI_ prefix are constant. Variables without L_ANSI_ prefix are set or empty depending on L_color_detect function. TheL_color_detect` function can be used to detect if the terminal and user wishes to have output with colors.

Example

echo "$L_RED""hello world""$L_RESET"

$L_COLOR_VARIABLES ¶

List of all color variable names set by L_color_enable or L_color_disable.

This is a bash array containing the names of all L_ color/style variables.

Example

local "${L_COLOR_VARIABLES[@]}"

L_color_enable ¶

The L_ color variables are set to the ANSI escape sequences.

Arguments: Takes no arguments

L_color_disable ¶

The L_ color variables are set to empty strings.

Arguments: Takes no arguments

Shellcheck disable= SC1007

L_term_has_color ¶

Detect if colors should be used on the terminal.

Argument: [$1] file descriptor to check, default: 1

Uses environment variables:

TERM
NO_COLOR

Return: 0 if colors should be used, nonzero otherwise

See: https://no-color.org/

L_color_detect ¶

Detect if colors should be used on the terminal.

Argument: [$1] file descriptor to check, default 1

Shellcheck disable= SC2120

See: https://en.wikipedia.org/wiki/ANSI_escape_code#Unix_environment_variables_relating_to_color_support

$L_ANSI_BOLD ¶

$L_ANSI_BRIGHT ¶

$L_ANSI_DIM ¶

$L_ANSI_FAINT ¶

$L_ANSI_STANDOUT ¶

$L_ANSI_UNDERLINE ¶

$L_ANSI_BLINK ¶

$L_ANSI_REVERSE ¶

$L_ANSI_CONCEAL ¶

$L_ANSI_HIDDEN ¶

$L_ANSI_CROSSEDOUT ¶

$L_ANSI_FONT0 ¶

$L_ANSI_FONT1 ¶

$L_ANSI_FONT2 ¶

$L_ANSI_FONT3 ¶

$L_ANSI_FONT4 ¶

$L_ANSI_FONT5 ¶

$L_ANSI_FONT6 ¶

$L_ANSI_FONT7 ¶

$L_ANSI_FONT8 ¶

$L_ANSI_FONT9 ¶

$L_ANSI_FRAKTUR ¶

$L_ANSI_DOUBLE_UNDERLINE ¶

$L_ANSI_NODIM ¶

$L_ANSI_NOSTANDOUT ¶

$L_ANSI_NOUNDERLINE ¶

$L_ANSI_NOBLINK ¶

$L_ANSI_NOREVERSE ¶

$L_ANSI_NOHIDDEN ¶

$L_ANSI_REVEAL ¶

$L_ANSI_NOCROSSEDOUT ¶

$L_ANSI_BLACK ¶

$L_ANSI_RED ¶

$L_ANSI_GREEN ¶

$L_ANSI_YELLOW ¶

$L_ANSI_BLUE ¶

$L_ANSI_MAGENTA ¶

$L_ANSI_CYAN ¶

$L_ANSI_LIGHT_GRAY ¶

$L_ANSI_DEFAULT ¶

$L_ANSI_FOREGROUND_DEFAULT ¶

$L_ANSI_BG_BLACK ¶

$L_ANSI_BG_BLUE ¶

$L_ANSI_BG_CYAN ¶

$L_ANSI_BG_GREEN ¶

$L_ANSI_BG_LIGHT_GRAY ¶

$L_ANSI_BG_MAGENTA ¶

$L_ANSI_BG_RED ¶

$L_ANSI_BG_YELLOW ¶

$L_ANSI_FRAMED ¶

$L_ANSI_ENCIRCLED ¶

$L_ANSI_OVERLINED ¶

$L_ANSI_NOENCIRCLED ¶

$L_ANSI_NOFRAMED ¶

$L_ANSI_NOOVERLINED ¶

$L_ANSI_DARK_GRAY ¶

$L_ANSI_LIGHT_RED ¶

$L_ANSI_LIGHT_GREEN ¶

$L_ANSI_LIGHT_YELLOW ¶

$L_ANSI_LIGHT_BLUE ¶

$L_ANSI_LIGHT_MAGENTA ¶

$L_ANSI_LIGHT_CYAN ¶

$L_ANSI_WHITE ¶

$L_ANSI_BG_DARK_GRAY ¶

$L_ANSI_BG_LIGHT_BLUE ¶

$L_ANSI_BG_LIGHT_CYAN ¶

$L_ANSI_BG_LIGHT_GREEN ¶

$L_ANSI_BG_LIGHT_MAGENTA ¶

$L_ANSI_BG_LIGHT_RED ¶

$L_ANSI_BG_LIGHT_YELLOW ¶

$L_ANSI_BG_WHITE ¶

$L_ANSI_BG_DEFAULT ¶

$L_ANSI_COLORRESET ¶

It resets color and font.