# Step 1 — Check Disk Usage Overview

Start by checking which partition is full:

df -h

Example output:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1        20G   19G  1G   95% /

• Use% = 95% → This partition is almost full

• Focus cleanup here

• 
  

---

## Step 2 — Identify Which Directories Use the Most Space

Use du (disk usage) command:

sudo du -h --max-depth=1 / | sort -hr

Explanation:

• du -h → human-readable sizes

• --max-depth=1 → show top-level folders only

• sort -hr → sort from largest to smallest

Example output:

8.5G /var
5.2G /home
3.0G /usr

• /var is the biggest folder → check inside

• 
  

---

## Step 3 — Drill Down into Large Directories

Go into the largest folder, e.g., /var:

cd /var
sudo du -h --max-depth=1 | sort -hr

Common culprits:

• /var/log → large log files

• /var/cache → package caches

• /var/lib/mysql → databases

• /var/tmp → temporary files

---

## Step 4 — Find Individual Large Files

To locate files bigger than, for example, 500MB:

sudo find / -type f -size +500M -exec ls -lh {} \; | awk '{ print $NF ": " $5 }'

Explanation:

• -type f → only files

• -size +500M → bigger than 500MB

• ls -lh → human-readable size

• awk → print file path and size

This gives a clear list of huge files to review.

---

## Step 5 — Use ncdu for Easier Navigation

ncdu is an interactive tool to explore disk usage.

Install:

sudo apt install ncdu -y     # Debian/Ubuntu
sudo yum install ncdu -y     # CentOS/RHEL

Run:

sudo ncdu /

• Navigate with arrow keys

• Identify large directories and files easily

• Delete safely from within ncdu using d key

• 
  

---

## Step 6 — Check Log Files

Logs can grow very fast. Check /var/log:

sudo du -sh /var/log/*

Common large log files:

• syslog

• auth.log

• mysql/error.log

• apache2/access.log

Clean logs safely:

sudo truncate -s 0 /var/log/syslog
sudo truncate -s 0 /var/log/mysql/error.log

---

## Step 7 — Clean Package Cache

Package managers often store old packages in cache:

Debian/Ubuntu

sudo apt clean

CentOS/RHEL

sudo yum clean all

Fedora

sudo dnf clean all

---

## Step 8 — Remove Old Kernels (Debian/Ubuntu)

Old Linux kernels can take GBs of space:

dpkg --list 'linux-image*' | grep ^ii
sudo apt autoremove --purge

---

## Step 9 — Check User Home Directories

Sometimes users store huge files in /home:

sudo du -sh /home/*

Delete or move unnecessary large files to external storage or cloud.

---

## Step 10 — Set Up Disk Monitoring

To prevent future disk-full situations:

• Install monitoring tools: Netdata, Glances, or Grafana + Prometheus

• Schedule automated cleanup: cron jobs for /tmp or /var/cache

• Alert when disk usage > 80%

Example cron job to clean temp files:

sudo crontab -e
# add:
0 3 * * * /usr/bin/find /tmp -type f -atime +7 -delete

Deletes files older than 7 days daily at 3AM.

---

## Beginner-Friendly Checklist

---

## Conclusion

A full Linux disk doesn’t have to be scary. By systematically checking:

• Disk usage by partition

• Largest directories

• Individual large files

• Logs, caches, old kernels, and user files

You can reclaim gigabytes of space safely. Use ncdu for interactive cleaning, set up monitoring, and schedule regular maintenance to prevent the disk from filling up again.