Without CRON

There are sometimes that it would be useful to use CRON or AT, but you do not have access. In those cases wrapping up the following in a nohup background command could help

while : ; do
  SLEEP=60
  NOW=$(date +%s)
  THEN=$(date -d "tomorrow 08:00" +%s)
  (( SLEEP = THEN - NOW ))
  echo Sleeping $SLEEP seconds
  sleep $SLEEP
  command_to_run
  sleep 60 # Just in case of issues
done