Filesystem 1K-blocks Used Available Use% Mounted on
udev 3939900 0 3939900 0% /dev
tmpfs 794004 2508 791496 1% /run
/dev/sda2 97905948 92533256 356324 100% /
tmpfs 3970008 0 3970008 0% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
tmpfs 3970008 0 3970008 0% /sys/fs/cgroup
/dev/loop1 56832 56832 0 100% /snap/core18/1988
/dev/loop2 101760 101760 0 100% /snap/core/11187
/dev/loop5 256 256 0 100% /snap/gtk2-common-themes/13
/dev/loop7 224256 224256 0 100% /snap/gnome-3-34-1804/72
/dev/loop0 101632 101632 0 100% /snap/core/11167
/dev/loop3 66432 66432 0 100% /snap/gtk-common-themes/1514
/dev/loop6 166784 166784 0 100% /snap/gnome-3-28-1804/145
/dev/loop9 66688 66688 0 100% /snap/gtk-common-themes/1515
/dev/loop8 56832 56832 0 100% /snap/core18/2066
/dev/loop11 114048 114048 0 100% /snap/shutter/27
/dev/loop4 224256 224256 0 100% /snap/gnome-3-34-1804/66
/dev/loop10 32896 32896 0 100% /snap/snapd/12057
/dev/loop12 52224 52224 0 100% /snap/snap-store/542
/dev/loop15 33152 33152 0 100% /snap/snapd/12159
/dev/loop13 52224 52224 0 100% /snap/snap-store/547
/dev/loop14 302720 302720 0 100% /snap/vlc/2288
/dev/nvme0n1p1 98304 33574 64730 35% /boot/efi
/dev/sda3 858014832 246173468 568186864 31% /home
tmpfs 794000 28 793972 1% /run/user/125
tmpfs 794000 76 793924 1% /run/user/1000
如何释放根空间？为什么要占用这么多空间？请帮忙。