$ Linux One Liners
Back to practice tasks

practice task

Disk Is Full: Prove Which Filesystem Is Out

A VPS starts returning write errors and an app cannot create new uploads. You need to decide whether the root filesystem, a mounted data volume, or inode exhaustion is the real problem before deleting anything.

Independent study support only. No affiliation, endorsement, exam dumps, or guaranteed exam results.

Try first

df -h && df -i

Goal

Identify the full filesystem and capture the first safe facts needed for cleanup.

Expected output

A table of mounted filesystems showing size, used space, available space, use percent, and inode usage. The important result is the mount point with very high Use% or IUse%.

Teaches

Start with filesystem-level evidence before hunting files. Disk space and inode exhaustion look similar to applications but require different fixes.

Common mistake

Running rm commands in random directories before proving which mount is full, or missing inode pressure because df -h still shows free bytes.

command set

Commands to know

  1. df -h
  2. df -i
  3. du -xhd1 /var | sort -h

Related lessons

Watch this command run

Example output from a temporary Linux lab

next practice

Find the Largest Files Under /var

The root filesystem is nearly full and /var looks suspicious. You need a read-only way to find the biggest files without crossing into other mounted filesystems.