编写定时任务脚本

cat >> /usr/local/bin/smem.sh <<-"EOF"

if [[ ! -d /var/log/smem ]];then
    mkdir -p /var/log/smem
fi
smem -tk >> /var/log/smem/smem.log
EOF

chmod 755 /usr/local/bin/smem.sh

配置定时任务

echo "" >> /etc/crontab
echo "* * * * * root flock -xn '/tmp/smem.lock' -c '/usr/local/bin/smem.sh' > /dev/null 2>&1" >> /etc/crontab
systemctl reload crond

配置日志轮转

cat >> /etc/logrotate.d/smem <<-"EOF"
/var/log/smem/smem.log {
    daily
    rotate 30
    compress
    delaycompress
    missingok
    notifempty
    create 644 root root
}
EOF

检查定时任务是否生效

# 查看 /var/log/cron
tail -1000 /var/log/cron |grep smem

# 这将显示过去 2 分钟内的 crond 日志条目
journalctl -u crond --since "2 minutes ago" | grep smem

[root@localhost lxm]# tail -1000 /var/log/cron |grep smem
Dec 20 10:13:01 localhost CROND[3378740]: (root) CMD (flock -xn '/tmp/smem.lock' -c '/usr/local/bin/smem.sh' > /dev/null 2>&1)
Dec 20 10:13:01 localhost CROND[3378739]: (root) CMDEND (flock -xn '/tmp/smem.lock' -c '/usr/local/bin/smem.sh' > /dev/null 2>&1)
[root@localhost lxm]# 
[root@localhost lxm]# journalctl -u crond --since "2 minutes ago" | grep smem
Dec 20 10:13:01 localhost.localdomain CROND[3378740]: (root) CMD (flock -xn '/tmp/smem.lock' -c '/usr/local/bin/smem.sh' > /dev/null 2>&1)
Dec 20 10:14:01 localhost.localdomain CROND[3388194]: (root) CMD (flock -xn '/tmp/smem.lock' -c '/usr/local/bin/smem.sh' > /dev/null 2>&1)