Bash / Shell 終端色彩與字型樣式

參考資料

參考FLOZz’ MISC的說明頁面

1. 核心語法結構

控制碼的基本格式為：

\e[<樣式/顏色代碼>m

• \e[（或 \033[、\x1b[）：CSI（Control Sequence Introducer）前綴。

• <代碼>：樣式代碼，多個代碼可用分號 ; 串接（例如 \e[1;31;40m 代表粗體 + 紅字 + 黑底）。

• m：Select Graphic Rendition（SGR）終止符號。

• \e[0m：重置控制碼。若最後沒有重置，後續整個終端的文字都會被染成該顏色！

基本使用範例

# 使用 echo (需加上 -e)
echo -e "\e[1;31m[ERROR]\e[0m 伺服器連線失敗"

# 更加推薦的 POSIX 標準寫法 (printf，免 -e 且各平台完全通用)
printf "\033[1;32m[SUCCESS]\033[0m 部署完成\n"

2. 文字樣式控制 (Text Formatting)

Formatting

Set

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

Reset

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

8/16 colors

Foreground (text)

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

Background

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

4. 進階：256 色與 24-bit True Color (RGB)

現代終端機（如 iTerm2、Windows Terminal、Alacritty、Kitty）皆已支援更豐富的 256 色與 RGB 真彩色：

• 256 色模式：

  • 前景：\e[38;5;<0-255>m

  • 背景：\e[48;5;<0-255>m

  • 範例：echo -e "\e[38;5;208m這是漂亮的橘色\e[0m"

• 24-bit True Color (RGB)：

  • 前景：\e[38;2;<R>;<G>;<B>m

  • 背景：\e[48;2;<R>;<G>;<B>m

  • 範例：echo -e "\e[38;2;255;100;0m自定義 RGB 珊瑚色\e[0m"

5. 工程師實戰：封裝易讀的日誌函式 (Script Boilerplate)

不要在 Shell Script 內散落難懂的 \e[31m。業界標準做法是在腳本開頭統一定義常數變數或封裝 Helper Function：

#!/bin/bash

# --- 定義色彩變數 ---
C_RESET="\033[0m"
C_BOLD="\033[1m"
C_RED="\033[1;31m"
C_GREEN="\033[1;32m"
C_YELLOW="\033[1;33m"
C_BLUE="\033[1;34m"
C_CYAN="\033[1;36m"

# --- 日誌函式 ---
log_info() {
    printf "${C_BLUE}[INFO]${C_RESET} %s\n" "$*"
}

log_success() {
    printf "${C_GREEN}[SUCCESS]${C_RESET} %s\n" "$*"
}

log_warn() {
    printf "${C_YELLOW}[WARN]${C_RESET} %s\n" "$*"
}

log_error() {
    printf "${C_RED}[ERROR]${C_RESET} %s\n" "$*" >&2
}

# --- 測試呼叫 ---
log_info "正在啟動 Docker Compose 服務..."
log_warn "記憶體剩餘不足 512MB"
log_success "Nextcloud 備份成功完成"
log_error "無法連接 MariaDB 資料庫"