• to see cron jobs for all users:
    for user in $(cut -f1 -d: /etc/passwd); do echo ""; echo "$user"; echo "--------------------"; sudo crontab -u $user -l; done
  • Ubuntu specific approach:
    v=/var/spool/cron/crontabs; for f in $(sudo ls $v); do echo ""; echo $f; echo "-------------------------"; sudo cat $v/$f; done
  • show currently running cron processes:
    • using tree of processes:
      ps -ejHf|grep -A20 -i "cron$"

      – adjust number of lines after “-A” switch to see what you need

    • using crontab for given user + list of processes:
      ps -ef|grep -F "$(sudo crontab -u ...here_your_username... -l|grep -v '#'|tr -s ' '|cut -d' ' -f6-99)"
  • opposite problem – show running scripts which are not cron jobs.
    • using crontab for all users + list of processes:
      ps -ef|grep -v "sshd\|-zsh\|sftp-server"|grep -i "sh\|coffee"|grep -F "$(for user in $(cut -f1 -d: /etc/passwd); do sudo crontab -u $user -l 2>/dev/null|grep -v '#'; done|tr -s ' '|cut -d' ' -f6-99)" -v

      – adjust excluded processes in 2 part of pipe and included processes in 3 part of pipe to your needs