Enhancing Shell Scripts with Colored Terminal Output

Enhancing Shell Scripts with Colored Terminal Output

#

Adding color to shell scripts is not just cosmetic—it significantly improves readability, usability, and user feedback. By visually distinguishing errors, warnings, and success messages, scripts become easier to understand and safer to operate, especially during automation and troubleshooting.

🎨 How ANSI Escape Codes Work

#

Terminal colors and text styles are controlled using ANSI escape codes. These are special character sequences interpreted by the terminal to modify how text is displayed.

The basic format is:

\033[<STYLE>;<COLOR>m<TEXT>\033[0m

Key components:

• \033[ or \e[: Starts the escape sequence
• <STYLE>;<COLOR>m: Defines formatting and color
• \033[0m: Resets formatting — always include this to avoid color bleed

🛠️ ANSI Color Code Reference

#

Foreground (Text) Colors

#

Background Colors

#

💻 Professional Scripting Pattern

#

To keep scripts clean and maintainable, define color codes as variables near the top of the script instead of repeating escape sequences.

#!/bin/bash

# Color definitions
RED='\033[31m'
GREEN='\033[32m'
YELLOW='\033[33m'
BLUE='\033[34m'
NC='\033[0m'   # Reset / No Color

log_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

log_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Example output
log_success "Backup completed successfully."
log_warning "Disk space is reaching 85%."
log_error "Database connection failed."

This approach improves consistency and makes future color changes trivial.

✨ Advanced Text Formatting

#

ANSI codes can be combined using semicolons to apply multiple styles at once:

• Bold red: \033[1;31m
• Underlined green: \033[4;32m
• Inverted colors: \033[7m

Compatibility Notes

#

• Terminal emulators (iTerm2, GNOME Terminal, VS Code, PuTTY) may render colors differently
• Always use echo -e or printf to ensure escape sequences are interpreted correctly
• For non-interactive scripts, consider disabling colors when output is redirected

Using colored output thoughtfully makes shell scripts clearer, safer, and more professional—especially in automation, monitoring, and system administration workflows.