Run different jobs at specific time points on weekdays using a systemd template unit

README.md

systemctl daemon-reload
systemctl enable --now job@{08:00,12:00,21:00}.timer

job.sh

#!/bin/bash -e

function fn_0800 {
  echo 'do something at 08:00'
}

function fn_1200 {
  echo 'do something at 12:00'
}

function fn_2100 {
  echo 'do something at 21:00'
}

function fn_default {
  echo 'Invalid invocation'
  date -R
  exit -1
}

case "$1" in
  08:00) fn_0800;;
  12:00) fn_1200;;
  21:00) fn_2100;;
  *) fn_default;;
esac

job@.service

[Unit]
Description=Run job.sh %i

[Service]
ExecStart=/path/to/job.sh %i

job@.timer

[Timer]
OnCalendar=Mon..Fri %i
AccuracySec=0

[Install]
WantedBy=timers.target