You can clean the cache and remove unused repositories in Ubuntu using the following commands:
sudo du -csh /var/cache/apt sudo apt-get autoclean sudo journalctl --disk-usage sudo apt-get autoclean sudo journalctl --vacuum-time=2d sudo apt-get remove package_name sudo apt-get autoremove --purge
Check top biggest folder in size:
sudo du -a / | sort -n -r | head -n 20
Remove docker log:
sudo sh -c "truncate -s 0 /var/lib/docker/containers/**/*-json.log"