My disk is 95% full but I don't know what's eating the space. How do I find out?

Try: sudo du -h -d 1 / 2>/dev/null | sort -rh | head -10

Info: du -h -d 1 scans top-level directory sizes. sort -rh ranks the largest directories first, and 2>/dev/null silences permission errors.

Examples:

• $ sudo du -h -d 2 /var | sort -rh | head -20
• $ ncdu /  # Interactive disk usage explorer (install: apt install ncdu)
• $ sudo du -sh /var/log/*.log | sort -rh | head

Note: Drill down step by step: start at /, then dive into the biggest directory. ncdu is a useful interactive alternative for browsing disk usage.