shell脚本遍历所有用户的 crontab 任务

遍历所有用户的 crontab 任务：

for user in $(cut -f1 -d: /etc/passwd); do
    echo "Crontab for user: $user"
    sudo crontab -u $user -l 2>/dev/null || echo "No crontab for user: $user"
    echo "-----------------------------"
done

输出:

Crontab for user: bin
No crontab for user: bin
-----------------------------
Crontab for user: daemon
No crontab for user: daemon
-----------------------------
Crontab for user: adm
No crontab for user: adm
-----------------------------
Crontab for user: lp
No crontab for user: lp
-----------------------------
Crontab for user: sync
No crontab for user: sync
-----------------------------
Crontab for user: shutdown
No crontab for user: shutdown
-----------------------------
Crontab for user: halt
No crontab for user: halt
-----------------------------
Crontab for user: mail
No crontab for user: mail
-----------------------------
Crontab for user: operator
No crontab for user: operator
-----------------------------
Crontab for user: games
No crontab for user: games
-----------------------------
Crontab for user: ftp
No crontab for user: ftp
-----------------------------
Crontab for user: nobody
No crontab for user: nobody

这个脚本会列出每个用户的 crontab 内容（如果有的话）。

用户级别：sudo crontab -u 用户名 -l
系统级别：cat /etc/crontab
查看所有用户的任务：sudo cat /var/spool/cron/crontabs/*