如何在 Linux 终端中更改文本颜色。

• 下载源代码 - 2.7 KB

引言

终端的默认文本输出是单色的，没有提供一个简单的方法来提供上下文。例如，您可能希望错误以红色显示，成功以绿色显示，或者重要信息以粗体输出。

向终端输出添加颜色非常简单，涉及在文本之前输出正确的控制字符。

终端颜色

要输出彩色文本，您需要使用 printf 或 echo -e（使用 -e 确保解释控制字符）来输出所需颜色的控制字符，然后输出您的文本，然后（为了整洁）将输出重置为默认值。下表列出了代码

Color	Foreground	背景
默认值	\033[39m	\033[49m
黑色	\033[30m	\033[40m
深红色	\033[31m	\033[41m
深绿色	\033[32m	\033[42m
深黄色（橙色）	\033[33m	\033[43m
深蓝色	\033[34m	\033[44m
深品红色	\033[35m	\033[45m
深青色	\033[36m	\033[46m
浅灰色	\033[37m	\033[47m
深灰色	\033[90m	\033[100m
红色	\033[91m	\033[101m
绿色	\033[92m	\033[101m
橙色	\033[93m	\033[103m
蓝色	\033[94m	\033[104m
品红色	\033[95m	\033[105m
青色	\033[96m	\033[106m
白色	\033[97m	\033[107m

重置代码是 \033[0m

前景色字符串的格式是

"\033[" + "<0 or 1, meaning normal or bold>;" + "<color code> + "m"

背景色字符串的格式是

"\033[" + "<color code>" + "m"

这些代码可以一起输出以同时更改前景色和背景色。

Using the Code

红色文本的简单示例

printf "\033[91mThis is red text\033[0m"

白色背景上的红色文本示例

printf "\033[91m\033[107mThis is red text on a white background\033[0m"

这有点麻烦，所以我创建了一些简单的子例程，这些例程提供了以更文明的方式输出文本的方法。

辅助函数

以下辅助函数允许您执行类似的操作

WriteLine "This is red text" "Red"
WriteLine "This is red text on a white background" "Red" "White"

容易得多。

useColor="true" # Set to false if you find your environment just doesn't handle colors well

# Returns a color code for the given foreground/background colors
# This code is echoed to the terminal before outputting text in
# order to generate a colored output.
#
# string foreground color name. Optional if no background provided.
#        Defaults to "Default" which uses the system default
# string background color name.  Optional. Defaults to $color_background
#        which is set based on the current terminal background
# returns a string
function Color () {

    local foreground=$1
    local background=$2

    if [ "$foreground" == "" ];  then foreground="Default"; fi
    if [ "$background" == "" ]; then background="$color_background"; fi

    local colorString='\033['

    # Foreground Colours
    case "$foreground" in
        "Default")      colorString='\033[0;39m';;
        "Black" )       colorString='\033[0;30m';;
        "DarkRed" )     colorString='\033[0;31m';;
        "DarkGreen" )   colorString='\033[0;32m';;
        "DarkYellow" )  colorString='\033[0;33m';;
        "DarkBlue" )    colorString='\033[0;34m';;
        "DarkMagenta" ) colorString='\033[0;35m';;
        "DarkCyan" )    colorString='\033[0;36m';;
        "Gray" )        colorString='\033[0;37m';;
        "DarkGray" )    colorString='\033[1;90m';;
        "Red" )         colorString='\033[1;91m';;
        "Green" )       colorString='\033[1;92m';;
        "Yellow" )      colorString='\033[1;93m';;
        "Blue" )        colorString='\033[1;94m';;
        "Magenta" )     colorString='\033[1;95m';;
        "Cyan" )        colorString='\033[1;96m';;
        "White" )       colorString='\033[1;97m';;
        *)              colorString='\033[0;39m';;
    esac

    # Background Colours
    case "$background" in
        "Default" )     colorString="${colorString}\033[49m";;
        "Black" )       colorString="${colorString}\033[40m";;
        "DarkRed" )     colorString="${colorString}\033[41m";;
        "DarkGreen" )   colorString="${colorString}\033[42m";;
        "DarkYellow" )  colorString="${colorString}\033[43m";;
        "DarkBlue" )    colorString="${colorString}\033[44m";;
        "DarkMagenta" ) colorString="${colorString}\033[45m";;
        "DarkCyan" )    colorString="${colorString}\033[46m";;
        "Gray" )        colorString="${colorString}\033[47m";;
        "DarkGray" )    colorString="${colorString}\033[100m";;
        "Red" )         colorString="${colorString}\033[101m";;
        "Green" )       colorString="${colorString}\033[102m";;
        "Yellow" )      colorString="${colorString}\033[103m";;
        "Blue" )        colorString="${colorString}\033[104m";;
        "Magenta" )     colorString="${colorString}\033[105m";;
        "Cyan" )        colorString="${colorString}\033[106m";;
        "White" )       colorString="${colorString}\033[107m";;
        *)              colorString="${colorString}\033[49m";;
    esac

    echo "${colorString}"
}


# Outputs a line, including linefeed, to the terminal using the given foreground / background
# colors 
#
# string The text to output. Optional if no foreground provided. Default is just a line feed.
# string Foreground color name. Optional if no background provided. Defaults to "Default" which
#        uses the system default
# string Background color name.  Optional. Defaults to $color_background which is set based on the
#        current terminal background
function WriteLine () {

    local resetColor='\033[0m'

    local str=$1
    local forecolor=$2
    local backcolor=$3

    if [ "$str" == "" ]; then
        printf "\n"
        return;
    fi

    # Note the use of the format placeholder %s. This allows us to pass "--" as strings without error
    if [ "$useColor" == "true" ]; then
        local colorString=$(Color ${forecolor} ${backcolor})
        printf "${colorString}%s${resetColor}\n" "${str}"
    else
        printf "%s\n" "${str}"
    fi
}

# Outputs a line without a linefeed to the terminal using the given foreground / background colors 
#
# string The text to output. Optional if no foreground provided. Default is just a line feed.
# string Foreground color name. Optional if no background provided. Defaults to "Default" which
#        uses the system default
# string Background color name.  Optional. Defaults to $color_background which is set based on the
#        current terminal background
function Write () {
    local resetColor="\033[0m"

    local forecolor=$1
    local backcolor=$2
    local str=$3

    if [ "$str" == "" ];  then
        return;
    fi

    # Note the use of the format placeholder %s. This allows us to pass "--" as strings without error
    if [ "$useColor" == "true" ]; then
        local colorString=$(Color ${forecolor} ${backcolor})
        printf "${colorString}%s${resetColor}" "${str}"
    else
        printf "%s" "$str"
    fi
}

处理深色模式和浅色模式

在许多 Linux 和 Unix 发行版中，终端是黑色背景，白色文本。在 macOS 上，默认是白色背景，黑色文本。有 方法 可以测试和猜测发生了什么，但最终您需要在您的系统上测试并确定什么对您有效。

我所做的是假设，如果我们在 mac 上，那么我们可以直接测试，否则我们假设黑底白字。然后，我也尝试坚持使用默认颜色，并且如果我想要一些颜色，我将坚持使用一些我知道可以在任何地方运行良好的预定义颜色。

# Gets the terminal background color. It's a very naive guess 
# returns an RGB triplet, values from 0 - 64K
function getBackground () {

    if [[ $OSTYPE == 'darwin'* ]]; then
        osascript -e \
        'tell application "Terminal"
            get background color of selected tab of window 1
        end tell'
    else

        # See https://github.com/rocky/shell-term-background/blob/master/term-background.bash
        # for a comprehensive way to test for background colour. For now we're just going to
        # assume that non-macOS terminals have a black background.

        echo "0,0,0" # we're making assumptions here
    fi
}

# Determines whether or not the current terminal is in dark mode (dark background, light text)
# returns "true" if running in dark mode; false otherwise
function isDarkMode () {

    local bgColor=$(getBackground)
    
    IFS=','; colors=($bgColor); IFS=' ';

    # Is the background more or less dark?
    if [ ${colors[0]} -lt 20000 ] && [ ${colors[1]} -lt 20000 ] && [ ${colors[2]} -lt 20000 ]; then
        echo "true"
    else
        echo "false"
    fi
}

一旦我们对我们正在处理的事情有了一个大致的了解，我就会执行

darkmode=$(isDarkMode)

# Setup some predefined colours. Note that we can't reliably determine the background 
# color of the terminal so we avoid specifically setting black or white for the foreground
# or background. You can always just use "White" and "Black" if you specifically want
# this combo, but test thoroughly
if [ "$darkmode" == "true" ]; then
    color_primary="Blue"
    color_mute="Gray"
    color_info="Yellow"
    color_success="Green"
    color_warn="DarkYellow"
    color_error="Red"
else
    color_primary="DarkBlue"
    color_mute="Gray"
    color_info="Magenta"
    color_success="DarkGreen"
    color_warn="DarkYellow"
    color_error="Red"
fi

要使用这些，请执行

WriteLine "Predefined colors on default background"
WriteLine

WriteLine "Default colored text" "Default"
WriteLine "Primary colored text" $color_primary
WriteLine "Mute colored text"    $color_mute
WriteLine "Info colored text"    $color_info
WriteLine "Success colored text" $color_success
WriteLine "Warning colored text" $color_warn
WriteLine "Error colored text"   $color_error

WriteLine
WriteLine "Default color on predefined background"
WriteLine

WriteLine "Default colored background" "Default"
WriteLine "Primary colored background" "Default" $color_primary
WriteLine "Mute colored background"    "Default" $color_mute
WriteLine "Info colored background"    "Default" $color_info
WriteLine "Success colored background" "Default" $color_success
WriteLine "Warning colored background" "Default" $color_warn
WriteLine "Error colored background"   "Default" $color_error 

在经典的 Linux 终端上

在 macOS 终端上

事情有点模糊，所以让我们添加一个额外的函数，它将在我们选择的任何背景上提供对比的前景。

# Returns the name of a color that will providing a contrasting foreground
# color for the given background color. This function assumes $darkmode has
# been set globally.
#
# string background color name. 
# returns a string representing a contrasting foreground colour name
function ContrastForeground () {

    local color=$1
    if [ "$color" == "" ]; then color="Default"; fi

    if [ "$darkmode" == "true" ]; then
        case "$color" in
            "Default" )     echo "White";;
            "Black" )       echo "White";;
            "DarkRed" )     echo "White";;
            "DarkGreen" )   echo "White";;
            "DarkYellow" )  echo "White";;
            "DarkBlue" )    echo "White";;
            "DarkMagenta" ) echo "White";;
            "DarkCyan" )    echo "White";;
            "Gray" )        echo "Black";;
            "DarkGray" )    echo "White";;
            "Red" )         echo "White";;
            "Green" )       echo "White";;
            "Yellow" )      echo "Black";;
            "Blue" )        echo "White";;
            "Magenta" )     echo "White";;
            "Cyan" )        echo "Black";;
            "White" )       echo "Black";;
            *)              echo "White";;
        esac
    else
        case "$color" in
            "Default" )     echo "Black";;
            "Black" )       echo "White";;
            "DarkRed" )     echo "White";;
            "DarkGreen" )   echo "White";;
            "DarkYellow" )  echo "White";;
            "DarkBlue" )    echo "White";;
            "DarkMagenta" ) echo "White";;
            "DarkCyan" )    echo "White";;
            "Gray" )        echo "Black";;
            "DarkGray" )    echo "White";;
            "Red" )         echo "White";;
            "Green" )       echo "Black";;
            "Yellow" )      echo "Black";;
            "Blue" )        echo "White";;
            "Magenta" )     echo "White";;
            "Cyan" )        echo "Black";;
            "White" )       echo "Black";;
            *)              echo "White";;
        esac
    fi
    
    echo "${colorString}"
}

然后，在 Color 子例程中，我们可以执行

function Color () {

    local foreground=$1
    local background=$2

    if [ "$foreground" == "" ]; then foreground="Default"; fi
    if [ "$background" == "" ]; then background="$color_background"; fi

    if [ "$foreground" == "Contrast" ]; then
        foreground=$(ContrastForeground ${background})
    fi
    
    ...

为了使我们的带有背景色的文本更易读，我们执行

WriteLine
WriteLine "Default contrasting color on predefined background"
WriteLine

WriteLine "Primary colored background" "Contrast" $color_primary
WriteLine "Mute colored background"    "Contrast" $color_mute
WriteLine "Info colored background"    "Contrast" $color_info
WriteLine "Success colored background" "Contrast" $color_success
WriteLine "Warning colored background" "Contrast" $color_warn
WriteLine "Error colored background"   "Contrast" $color_error 

在 Linux 终端上的结果

...以及在 macOS 终端上