ZSH function to stop and restart a service under launchd - written on high sierra 10.13.6 for zsh 5.7.1

svc_bounce.zsh

################################################################################
# restarts a service in launchd.  assumes you have
# https://github.com/MarkTiedemann/countdown-cli installed. but will run `sleep`
# if you don't.
#
# usage: svc_bounce domain/svc_target timeout
# timeout is needed so launchd can shut the service down gracefully.
################################################################################
function svc_bounce() {
  local -r svc="${1}";
  local -r timeout="${2:-10}"
  local sudo_cmd;
  local svc_dir="Library/LaunchAgents";
  local svc_dirs=( "${HOME}/${svc_dir}" "${HOME}/${svc_dir/Agent/Daemon}" "/${svc_dir}" "/${svc_dir/Agent/Daemon}" "/System/${svc_dir}" "/System/${svc_dir/Agent/Daemon}" );
  local err=1
  ## zsh indices are 1-indexed.
  local counter=1
  local pause_cmd="$(command -v countdown) -s";

  ## do we need to sudo?
  if [[ "${svc#system/}" != "${svc}" ]];
  then
    sudo_cmd="/usr/bin/sudo";
    svc_dir="/Library/LaunchAgents";
  fi;

  ### countdown or sleep?
  [[ ${pause_cmd} == "" ]] && pause_cmd="$(command -v sleep)";


  ## bootout/stop svc, wait if needed
  eval "${sudo_cmd}" /bin/launchctl bootout "${svc}" 2>/dev/null;
  if [[ "${timeout}" -gt 0 ]];
  then
    echo "Booting out ${svc##*/}.  We will wait ${timeout} seconds to restart.";
    eval "${pause_cmd}" "${timeout}";
    echo "Let's begin.";
  fi;

  ## step thru potential locations of svc, bootstrap and kickstart.
  while [[ "${err}" -gt 0 ]] && [[ "${counter}" -lt "${#svc_dirs[@]}" ]];
  do
    eval "${sudo_cmd}" /bin/launchctl bootstrap "${svc%/*}" "${svc_dirs[${counter}]}/${svc##*/}.plist" 2>/dev/null;
    let err="${?}";
    if [ "${err}" -gt 0 ]; then
      echo "plist not found in ${svc_dirs[${counter}]}";
    else
      echo "bootstrapping ${svc} from ${svc_dirs[${counter}]}/${svc##*/}.plist...";
      break;
    fi;
    let counter="$(( ${counter} + 1 ))";
  done;
  if [[ ${err} -gt 0 ]] || [[ ! ${counter} -lt ${#svc_dirs[@]} ]]; then
    echo "could not bootstrap ${svc}!";
  else
    echo "Service ${svc##*/} bootstrapped. Kickstarting.";
    eval "${sudo_cmd}" /bin/launchctl kickstart -pk "${svc}";
  fi;
}