Colors with ANSI Escape Code

ANSI Escape Code

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ANSI Escape Code is a technique used to control cussor location, color, font styling on a text terminals, aka “command line” or “cmdline” or “cli”.

In HTML world, all these can be done easily. In other environment, it may not be as simple as in HTML world.

Below are the examples, from Wikipedia, how it can be used to change the display on the terminal emulator.

ANSI Color Code

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Bash (color codes)

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Use the following template to print color text.

echo -e "\e[COLORmSample Text\e[0m"
echo -e "\e[COLOR1;COLOR2mSample Text\e[0m"
echo -e "\e[MODE;COLOR1;COLOR2mSample Text\e[0m"

Example

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Simple test.

$ echo -e "\e[37m White_Text \e[0m"
 White_Text
$ echo -e "\e[1;34m Light_Blue_Text \e[0m"
 Light_Blue_Text
$ echo -e "\e[1;33;4;44m Underlined Yellow on Blue \e[0m"
 Underlined Tellow on Blue

Test all colors with a for-loop.

for code in {0..255}
    do echo -e "\e[38;5;${code}m"'\\e[38;5;'"$code"m"\e[0m"
done

Bash (flasher)

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The following Bash function flashes the terminal until the user presses a key.

flasher () { while true; do printf \\e[?5h; sleep 0.1; printf \\e[?5l; read -s -n1 -t1 && break; done; }

Or, you can add it to shell script file.

#!/bin/bash

flasher () { 
  while true 
    do 
      printf \\e[?5h 
      sleep 0.1 
      printf \\e[?5l 
      read -s -n1 -t1 && break 
    done 
  }

PowerShell

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Testing color with ANSI Escape code in PowerShell.

PS> $esc = [char]27
PS> write-host "$esc[32m Green $esc[0m"
 Green
PS> 

Links

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• Wikipedia ANSI escape code
• VT100 User Guide
• Tool: ANSI