Tools
Cron
Read five-field schedules and avoid timezone and overlap surprises.
Schedule fields
minute hour day-of-month month day-of-weekStandard five-field order; platform formats can differ0 9 * * 1-5Run at 09:00 Monday through Friday*/15 * * * *Run every 15 minutes0 0 1 * *Run at midnight on the first day of each monthCommon schedules
0 * * * *Run at the start of each hour30 18 * * *Run at 18:30 every day0 10 * * 0Run on Sundays at 10:000 0 * * *Run daily at midnight in the scheduler timezoneLocal crontab
crontab -lInspect your current crontabcrontab -eEdit your user crontab/usr/bin/python3 /srv/task.py >> /srv/task.log 2>&1Use absolute paths and redirect both streamsflock -n /tmp/task.lock /srv/task.shOn Linux, skip overlapping runs when flock is available