how do I keep my file system root from getting full 20.04?

[handydoug]

I get an error that pops up saying that my file root system has low space.
In the past, I deleted some things and it was okay for a while. How can I keep it from filling up, please?
Here is output of "df -h":
Filesystem Size Used Avail Use% Mounted on
udev 7.8G 0 7.8G 0% /dev
tmpfs 1.6G 3.7M 1.6G 1% /run
/dev/nvme0n1p3 19G 17G 740M 96% /
tmpfs 7.9G 82M 7.8G 2% /dev/shm
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 7.9G 0 7.9G 0% /sys/fs/cgroup
/dev/loop0 56M 56M 0 100% /snap/core18/2074
/dev/loop1 56M 56M 0 100% /snap/core18/2066
/dev/loop2 62M 62M 0 100% /snap/core20/1026
/dev/loop4 296M 296M 0 100% /snap/vlc/2288
/dev/loop3 277M 277M 0 100% /snap/gimp/372
/dev/loop5 269M 269M 0 100% /snap/gimp/367
/dev/loop6 244M 244M 0 100% /snap/gnome-3-38-2004/39
/dev/nvme0n1p1 975M 7.9M 967M 1% /boot/efi
/dev/loop7 65M 65M 0 100% /snap/gtk-common-themes/1514
/dev/loop8 62M 62M 0 100% /snap/core20/975
/dev/nvme0n1p4 867G 316G 507G 39% /home
/dev/loop9 302M 302M 0 100% /snap/telegram-desktop/2841
/dev/loop10 33M 33M 0 100% /snap/snapd/12398
/dev/loop11 219M 219M 0 100% /snap/gnome-3-34-1804/66
/dev/loop12 51M 51M 0 100% /snap/snap-store/547
/dev/loop13 51M 51M 0 100% /snap/snap-store/542
/dev/loop14 163M 163M 0 100% /snap/gnome-3-28-1804/145
/dev/loop15 296M 296M 0 100% /snap/vlc/2344
/dev/loop16 219M 219M 0 100% /snap/gnome-3-34-1804/72
/dev/loop17 302M 302M 0 100% /snap/telegram-desktop/2831
/dev/loop18 66M 66M 0 100% /snap/gtk-common-themes/1515
/dev/loop19 261M 261M 0 100% /snap/kde-frameworks-5-core18/32
/dev/loop20 33M 33M 0 100% /snap/snapd/12159
tmpfs 1.6G 40K 1.6G 1% /run/user/1000
/dev/sda1 954G 221G 734G 24% /media/doug/ADATA SE800

Thanks, Doug

 

[Tolkem]

How can I keep it from filling up, please?

Is that a 1 TB disk? Can you install ncdu?

sudo apt install ncdu

This is a disk usage reporting tool, quite handy I must say. Once installed, in the terminal, run

ncdu /var

just to check whether there are old downloaded pkgs wasting space there. Then, run

ncdu /

copy/paste the output here in your reply, and if possible use code tags, please. Just click in the " ... " menu, right next to the emoji(smily face) and choose code

then paste the output. should be something like

--- /var --------------------------------------------------------------------------------------------------------------------------------------------------------------
. 962,3 MiB [##########] /lib                                                                                                                                         
. 473,6 MiB [####      ] /log
. 124,4 MiB [#         ] /cache
    4,8 MiB [          ] /backups
. 240,0 KiB [          ] /tmp
.  36,0 KiB [          ] /spool
e   4,0 KiB [          ] /snap
e   4,0 KiB [          ] /opt
e   4,0 KiB [          ] /mail
e   4,0 KiB [          ] /local
@   0,0   B [          ]  lock
@   0,0   B [          ]  run