Remove Unused Kernels
🔍 Step 1: Check What’s Using Space
Run this in your terminal:
sudo du -h --max-depth=1 / | sort -hr | head -n 10
This shows the largest directories in root. Investigate the biggest ones (like /var, /usr, /home, etc.).
🧹 Step 2: Clean Package Cache
sudo apt clean
This removes cached .deb files in /var/cache/apt/archives, which can take up a lot of space.
🧹 Step 3: Remove Unused Kernels
Check your current kernel:
uname -r
List installed kernels:
dpkg --list | grep linux-image
Remove old kernels (except the current one):
sudo apt remove --purge linux-image-X.X.X-XX-generic
# sudo apt remove --purge linux-image-6.1.0-33-amd64
# sudo apt purge linux-image-6.1.0-32-amd64
Be very careful not to remove the current or only working kernel.
🧹 Step 4: Remove Orphaned Packages
sudo apt autoremove
This removes packages installed as dependencies but no longer needed.
🧹 Step 5: Clean Journal Logs (if using systemd)
sudo journalctl --vacuum-time=3d
This deletes logs older than 3 days (adjust as needed).
🧼 Step 6: Identify & Delete Large Files
Find files larger than 100MB:
sudo find / -type f -size +100M -exec ls -lh {} \; 2>/dev/null | sort -k 5 -rh | head -n 20
Check if any are safe to delete (e.g., large ISO files, crash dumps, logs, etc.).
🧭 Optional: Move Files Off Root
If /home or an external drive has space:
sudo mv /path/to/large/file /home/youruser/
Or compress rarely used files:
gzip /path/to/large/file
🚨 Reboot After Cleaning
Once you’ve freed a few GB, reboot to ensure system services restart normally:
sudo reboot
After you’ve removed the old kernels and run sudo apt autoremove, you can check how much space is now free on your root partition with:
df -h /
This will output something like:
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 20G 18G 1.5G 93% /
Look at the “Avail” column — it shows how much space is now free on your / partition.