human.bash

#!/usr/bin/env bash
#
# Print a human readable timestamp to the terminal
# given a number representing seconds
#
# Author: Dave Eddy <dave@daveeddy.com>
# Date: 8/18/2014
# License: MIT

human() {
	local seconds=$1
	if ((seconds < 0)); then
		((seconds *= -1))
	fi

	local times=(
	$((seconds / 60 / 60 / 24 / 365)) # years
	$((seconds / 60 / 60 / 24 / 30))  # months
	$((seconds / 60 / 60 / 24 / 7))   # weeks
	$((seconds / 60 / 60 / 24))       # days
	$((seconds / 60 / 60))            # hours
	$((seconds / 60))                 # minutes
	$((seconds))                      # seconds
	)
	local names=(year month week day hour minute second)

	local i j
	for ((i = 0; i < ${#names[@]}; i++)); do
		if ((${times[$i]} > 1)); then
			echo "${times[$i]} ${names[$i]}s"
			return
		elif ((${times[$i]} == 1)); then
			echo "${times[$i]} ${names[$i]}"
			return
		fi
	done
	echo '0 seconds'
}

for seconds in "$@"; do
	human "$seconds"
done