On 2/27/20 8:01 AM, Tobias Kirchhofer wrote: > Hi, > > we experience difficulties with crond behaviour sending mail since CentOS 8.1. The cron job is the same like we used in CentOS 7. > > crontab -l > /usr/bin/python3 -c 'import random; import time; time.sleep(random.random() * 3600)' && /usr/local/bin/backup.sh > Agreed on the missing timespec (invalid cron line), but why the mile-long python rather than the simpler: sleep $((RANDOM \% 3600)) Recall percent signs (%) in crontabs means put a newline here, so it needs to be quoted to disable. Regardless, you say it's not sending mail...that could be silence or say if /usr/bin/python3 didn't exist, should output an error. did you check your mail logs?