Is dir newer

dir_is_newer.bash

#!/bin/bash -e

src_dir=$(readlink -f $1)
dst_dir=$(readlink -f $2)
src_timestamp=$(find $src_dir -type f -printf "%T+\n" | sort | tail -1)
dst_timestamp=$(find $dst_dir -type f -printf "%T+\n" | sort | tail -1)

if [ -z $dst_timestamp ]; then
    echo "$dst_dir does not exist"
elif [[ $src_timestamp > $dst_timestamp ]]; then
    echo "$src_dir is newer than $dst_dir"
else
    echo "$src_dir is not newer than $dst_dir"
    exit 1
fi