linux的df命令用来查看磁盘情况的，很简单，但工作中很常用。/dev/sda1大小总是在不断变化，也要防止其爆满。
virtual-machine:/mnt/hgfs/vmShare$ df -h 文件系统 容量 已用 可用 已用% 挂载点 udev 943M 0 943M 0% /dev tmpfs 195M 3.2M 192M 2% /run /dev/sda1 20G 18G 1.5G 92% / tmpfs 974M 0 974M 0% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 974M 0 974M 0% /sys/fs/cgroup /dev/loop0 3.8M 3.8M 0 100% /snap/gnome-system-monitor/127 /dev/loop1 45M 45M 0 100% /snap/gtk-common-themes/1353 /dev/loop2 157M 157M 0 100% /snap/gnome-3-28-1804/110 /dev/loop3 141M 141M 0 100% /snap/gnome-3-26-1604/97 /dev/loop4 157M 157M 0 100% /snap/gnome-3-28-1804/91 /dev/loop5 1.0M 1.0M 0 100% /snap/gnome-logs/73 /dev/loop6 1.0M 1.0M 0 100% /snap/gnome-logs/81 /dev/loop7 4.3M 4.3M 0 100% /snap/gnome-calculator/536 /dev/loop8 15M 15M 0 100% /snap/gnome-characters/399 /dev/loop12 15M 15M 0 100% /snap/gnome-characters/375 /dev/loop13 4.3M 4.3M 0 100% /snap/gnome-calculator/544 /dev/loop14 55M 55M 0 100% /snap/core18/1650 /dev/loop9 45M 45M 0 100% /snap/gtk-common-themes/1440 /dev/loop11 141M 141M 0 100% /snap/gnome-3-26-1604/98 /dev/loop16 3.8M 3.8M 0 100% /snap/gnome-system-monitor/123 /dev/loop15 90M 90M 0 100% /snap/core/8268 /dev/loop10 55M 55M 0 100% /snap/core18/1279 /dev/loop17 90M 90M 0 100% /snap/core/8213 tmpfs 195M 16K 195M 1% /run/user/121 vmhgfs-fuse 178G 35G 143G 20% /mnt/hgfs tmpfs 195M 40K 195M 1% /run/user/1000 /dev/sr0 1.9G 1.9G 0 100% /media/mapan/Ubuntu 18.04.1 LTS amd64
