Ghost Disk Usage

Reclaim disk space from a deleted file still held open by a running process.

A advanced Linux challenge worth 20 points. Solve it hands-on in a real Linux environment in your browser - no local setup, no fake shells.

The Challenge

df -h shows /var at 98%. du -sh /var/* accounts for only 40 GB of a 100 GB partition. A deleted log file is still held open by a process, keeping the blocks allocated.

Your tasks:

• Confirm the gap between df and du output
• Find the deleted-but-open file: lsof +L1
• Identify the PID and file descriptor number from lsof output
• Truncate the fd without closing it: > /proc/<PID>/fd/<FD>
• Verify df shows space reclaimed
• Write the reclaimed info to /tmp/reclaimed.txt
• Run check to validate