查找大文件：
sudo find / -type f -size +100M -exec ls -lh {} \; 2>/dev/null | sort -k5 -hr
-rw-r--r-- 1 root root 13G Aug 13 18:35 /usr/local/nginx/logs/access.log
-rw------- 1 root root 3.2G Apr 27 03:33 /var/log/messages-20250427
清理：
sudo truncate -s 0 /usr/local/nginx/logs/access.log
sudo rm -f /var/log/messages-*
这条命令的意思是清理并删除 1 分钟之前的所有系统日志，以释放磁盘空间。
sudo journalctl --vacuum-time=1m
查看磁盘情况
df -h
查看磁盘内存
free -h
查看前 10 个占用内存最多的进程，显示内存大小（MB）
ps aux --sort=-%mem | head -11 | awk 'NR==1{printf "%-8s %6s %6s %10s %s\n", "PID", "USER", "%MEM", "RSS(MB)", "COMMAND"} NR>1{printf "%-8s %6s %6.1f %10.1f %s\n", $2, $1, $4, $6/1024, substr($0, index($0,$11))}'
查看Mysql的log日志
sudo tail -50 /usr/local/mysql/data/*.err
查看mysql的网络连接
sudo ss -tulpn | grep :3306