How to find the largest directories in Linux

Finding the largest directories quickly identifies where disk space is concentrated, enabling targeted cleanup before full filesystems cause write failures, crashes, or stalled updates.

On Linux, du walks a directory tree and totals disk usage, while --max-depth limits reporting to a summary level that keeps scans readable. Piping the results into sort with human-size sorting highlights the heaviest paths first, making it easier to decide where to drill down next.

Directory scans can be slow on large trees and the reported sizes reflect allocated disk blocks rather than the apparent size of sparse files. The --apparent-size option switches to logical sizes when needed. Running commands with sudo reduces permission gaps, and confirming the target directory size before removing data helps avoid deleting the wrong subtree.

1. Summarize top-level directory sizes on the filesystem mount.

   $ sudo du -xh --max-depth=1 / 2>/dev/null | sort -hr | head -n 12
   5.7G	/
   2.8G	/usr
   833M	/var
   6.3M	/etc
   84K	/tmp
   52K	/home
   16K	/root
   16K	/lost+found
   8.0K	/snap
   8.0K	/media
   4.0K	/srv
   4.0K	/sbin.usr-is-merged

   -x keeps the scan on the same filesystem, avoiding sizes from other mounts under the target path.

2. Summarize immediate subdirectories inside a large top-level directory.

   $ sudo du -xh --max-depth=1 /var | sort -hr | head -n 10
   833M	/var
   402M	/var/log
   278M	/var/lib
   152M	/var/cache
   2.1M	/var/backups
   52K	/var/tmp
   16K	/var/spool
   4.0K	/var/snap
   4.0K	/var/opt
   4.0K	/var/mail

3. Drill into a heavy subtree by increasing --max-depth.

   $ sudo du -xh --max-depth=2 /var/lib | sort -hr | head -n 12
   278M	/var/lib
   229M	/var/lib/apt/lists
   229M	/var/lib/apt
   38M	/var/lib/dpkg
   36M	/var/lib/dpkg/info
   5.8M	/var/lib/ubuntu-advantage
   5.7M	/var/lib/ubuntu-advantage/apt-esm
   3.6M	/var/lib/command-not-found
   1.8M	/var/lib/fwupd/metadata
   1.8M	/var/lib/fwupd
   696K	/var/lib/systemd
   396K	/var/lib/systemd/deb-systemd-helper-enabled

   Running du on very large directory trees can take a long time and generate heavy disk I/O, which may impact busy systems.

4. Scan home directories to spot space-heavy users or project trees.

   $ sudo du -xh --max-depth=1 /home | sort -hr | head -n 10
   52K	/home
   48K	/home/user

5. Confirm the reported size for a candidate directory before cleanup.

   $ sudo du -shx /var/lib
   278M	/var/lib

   Replace /var/lib with the directory identified as large in the previous steps.