Solution to Reddit Daily Programmer 201

count_days.sh

#!/usr/pkg/bin/zsh
dateMath() {
        todayMonth=$(date "+%m/%d/%y" | awk -F\/ '{print $1}' | sed "s/^0//")
        todayDay=$(date "+%m/%d/%y" | awk -F\/ '{print $2}' | sed "s/^0//")
        todayYear=$(date "+%m/%d/%y" | awk -F\/ '{print $3}' | sed "s/^0//")
        today="$todayMonth/$todayDay/$todayYear"
        current=$(date -d $today +%s)
        submitted=$(date -d $1 +%s)
        diffDays=$((($submitted - $current) / 86400))
        echo "You must wait $diffDays days from $today to $1"
}

input="2016 2 9"
year=$(echo $input | awk '{print $1}')
month=$(echo $input | awk '{print $2}')
day=$(echo $input | awk '{print $3}')
inputDate="$month/$day/$year"
dateMath $inputDate