[UBUNTU] [RASPBERRY] How can I free up space?

First of all, install NCDU

NCDU stands for NCurse Disk Usage which is Linux program that displays Disk usage statistics in a Ncurse menu, which makes things easier where you don’t know exactly where to start

apt install ncdu

Use dpkg-query to find the largest packages and remove the ones you don't need anymore.

dpkg-query --show --showformat='${Package;-50}\t${Installed-Size}\n' | sort -k 2 -n | grep -v deinstall | awk '{printf "%.3f MB \t %s\n", $2/(1024), $1}

If the application has been installed via the package manager, all you have to do is run

sudo apt-get remove <application_name>

sudo apt-get autoremove

#check partition sizes

df -h

#check directory size

du -s -h /var/log/

#check every directory and file sizes under a dir.

du -s -h /var/log/*