#!/bin/sh set -eu usage() { cat <<-'EOF' Usage: now [-E] EOF } EXTENDED=false while getopts 'E' flag; do case "$flag" in (E) EXTENDED=true ;; (*) usage >&2 exit 2 ;; esac done shift $((OPTIND - 1)) # FIXME: neither %s or %N are POSIX if [ "$EXTENDED" = true ]; then date '+%s.%N' else date '+%s' fi