finga-utils/birthdays/birthdays.sh

#!/bin/bash
set -e

conf_file="$HOME/.birthdays"
days_left=30

# read file into line seperated string array (could become sorted)
readarray lines < "$conf_file"

# iterate over each field
for i in "${lines[@]}"; do
    # get date
    date=$(cut -d" " -f1 <<< "$i")

    # calculate days from now until $date if date fails it could be 2/29
    days=$(( 10#$(date -d "$date" +%j 2>/dev/null || echo 059) - 10#$(date +%j) ))

    # if $days is in range of $days_left
    if  [ 0 -lt "$days" ] && [ "$days" -le "$days_left" ];then
        # if $days is between less than 8: output red counter
        if [ "$days" -le 7 ];then
            echo -e "\\033[31m$(cut -f2- <<< "$i") in $days days\\033[m"
        # if $days is between 8-15: output yellow counter
        elif [ "$days" -le $((days_left / 2)) ];then
            echo -e "\\033[33m$(cut -f2- <<< "$i") in $days days\\033[m"
        # else print green counter
        else
            echo -e "\\033[32m$(cut -f2- <<< "$i") in $days days\\033[m"
        fi
    elif [ "$days" -eq 0 ];then
        echo -e "\033[31;5m$(cut -f2- <<< "$i") is today\033[0m"
    fi
done