How to change the output color of echo in Linux

Question

I am trying to print a text in the terminal using echo command.

I want to print the text in a red color. How can I do that?

Answer 1

This is the color switch \033[. See history.

Color codes are like 1;32 (Light Green), 0;34 (Blue), 1;34 (Light Blue), etc.

We terminate color sequences with a color switch \033[ and 0m, the no-color code. Just like opening and closing tabs in a markup language.

  SWITCH="\033["
  NORMAL="${SWITCH}0m"
  YELLOW="${SWITCH}1;33m"
  echo "${YELLOW}hello, yellow${NORMAL}"

Simple color echo function solution:

cecho() {
  local code="\033["
  case "$1" in
    black  | bk) color="${code}0;30m";;
    red    |  r) color="${code}1;31m";;
    green  |  g) color="${code}1;32m";;
    yellow |  y) color="${code}1;33m";;
    blue   |  b) color="${code}1;34m";;
    purple |  p) color="${code}1;35m";;
    cyan   |  c) color="${code}1;36m";;
    gray   | gr) color="${code}0;37m";;
    *) local text="$1"
  esac
  [ -z "$text" ] && local text="$color$2${code}0m"
  echo "$text"
}

cecho "Normal"
cecho y "Yellow!"