Bash function for colored output. (source: https://stackoverflow.com/questions/5947742/how-to-change-the-output-color-of-echo-in-linux#answer-28709668)

cecho.sh

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 -e "$text" # The -e flag is needed on macOS. Other systems might not need it.
}

cecho "Normal"
cecho y "Yellow!"