function for the text coloring/transformation in terminal

bash_ansi_format

#!/bin/bash

#######################################
# Formats a string with ANSI codes
# Arguments:
#   $1 the string to be formatted
#   FG_* the foreground color, available values
#       FG_BLACK
#       FG_RED
#       FG_GREEN
#       FG_YELLOW
#       FG_BLUE
#       FG_PURPLE
#       FG_CYAN
#       FG_GREY
#   BG_* the background color, available values
#       BG_BLACK
#       BG_RED
#       BG_GREEN
#       BG_YELLOW
#       BG_BLUE
#       BG_PURPLE
#       BG_CYAN
#       BG_GREY
#   TXT_* the text transformation, available values
#       TXT_RESET
#       TXT_NORMAL
#       TXT_BOLD
#       TXT_ITALIC
#       TXT_UNDERLINE
#       TXT_BLINK
#       TXT_NEGATIVE
#       TXT_CONCEALED
#       TXT_CROSSED_OUT
#       TXT_FRAMED
#       TXT_ENCIRCLED
#       TXT_OVERLINED
# Returns:
#   None
# Usage:
#   ansi_format "Hello world" FG_GREEN
#   ansi_format "Hello world" BG_PURPLE
#   ansi_format "Hello world" TXT_BOLD
#   ansi_format "Hello world" FG_YELLOW BG_BLACK TXT_BLINK
#######################################
function ansi_format {
    STRING=$1
    FG_COLOR=-1
    BG_COLOR=-1
    TXT_TRANSFORMATION=-1
    FORMAT=''

    for argument in "$@"; do
        if [[ ${argument} == FG_* ]]; then
            FG_COLOR=${argument}
            continue
        fi
        if [[ ${argument} == BG_* ]]; then
            BG_COLOR=${argument}
            continue
        fi
        if [[ ${argument} == TXT_* ]]; then
            TXT_TRANSFORMATION=${argument}
            continue
        fi
    done

    declare -A FG_COLORS
    FG_COLORS[FG_BLACK]=30;
    FG_COLORS[FG_RED]=31;
    FG_COLORS[FG_GREEN]=32;
    FG_COLORS[FG_YELLOW]=33;
    FG_COLORS[FG_BLUE]=34;
    FG_COLORS[FG_PURPLE]=35;
    FG_COLORS[FG_CYAN]=36;
    FG_COLORS[FG_GREY]=37;

    declare -A BG_COLORS
    BG_COLORS[BG_BLACK]=40;
    BG_COLORS[BG_RED]=41;
    BG_COLORS[BG_GREEN]=42;
    BG_COLORS[BG_YELLOW]=43;
    BG_COLORS[BG_BLUE]=44;
    BG_COLORS[BG_PURPLE]=45;
    BG_COLORS[BG_CYAN]=46;
    BG_COLORS[BG_GREY]=47;

    declare -A TXT_TRANSFORMATIONS
    TXT_TRANSFORMATIONS[TXT_RESET]=0;
    TXT_TRANSFORMATIONS[TXT_NORMAL]=0;
    TXT_TRANSFORMATIONS[TXT_BOLD]=1;
    TXT_TRANSFORMATIONS[TXT_ITALIC]=3;
    TXT_TRANSFORMATIONS[TXT_UNDERLINE]=4;
    TXT_TRANSFORMATIONS[TXT_BLINK]=5;
    TXT_TRANSFORMATIONS[TXT_NEGATIVE]=7;
    TXT_TRANSFORMATIONS[TXT_CONCEALED]=8;
    TXT_TRANSFORMATIONS[TXT_CROSSED_OUT]=9;
    TXT_TRANSFORMATIONS[TXT_FRAMED]=51;
    TXT_TRANSFORMATIONS[TXT_ENCIRCLED]=52;
    TXT_TRANSFORMATIONS[TXT_OVERLINED]=53;

    if [ ${#FG_COLORS[$FG_COLOR]} != 0 ]; then
        FORMAT=${FG_COLORS[$FG_COLOR]}
    fi
    if [ ${#BG_COLORS[$BG_COLOR]} != 0 ]; then
        FORMAT="${FORMAT};${BG_COLORS[$BG_COLOR]}"
    fi
    if [ ${#TXT_TRANSFORMATIONS[$TXT_TRANSFORMATION]} != 0 ]; then
        FORMAT="${FORMAT};${TXT_TRANSFORMATIONS[$TXT_TRANSFORMATION]}"
    fi

    echo -e -n "\033[0m\033[0${FORMAT}m${STRING}\033[0m"
}