#!/bin/zsh
# crontab usage:
# * * * * * ~/sh/minutemaid 9 do something # runs every nine minutes
local bottom=0 strip=0 interval=2 opt=
while getopts ':h' opt; do
    case $opt in
    ?)  local fd=0
        [ $opt = h ] && fd=0 || fd=2
        echo -E "usage: $0 {period} {command} [{args...}]" >&$fd
        [ $opt = h ] && return 0 || return 1;;
    esac
done
shift $((OPTIND-1))

local period=${1:?no period specified}
shift
local cmd=${1:?no command specified}
shift

sec="$(date +%s)"
let min=sec/60
let mod=min%period
[ $mod -eq 0 ] && "$cmd" "$@"