If you wish to find the largest folders/files in a specific directory, you can use the following commands.
1. Find largest folders
For example to find the largest 20 directories in the /var/log directory, use this:
sudo du -hx /var/log | sort -hr | head -20
2. Find largest files
Alternatively, if you wish to find the largest 20 individual files in the /var/log directory, you can use this:
sudo find /var/log -type f -exec du -Sh {} + | sort -rh | head -n 20