Linux Commands Cheat Sheet 2026: 100 Essential Commands Every Developer Needs

Whether you're managing a VPS, deploying applications, or troubleshooting server issues, knowing the right Linux commands saves hours of work. This cheat sheet covers the 100 most essential commands organized by category, with practical examples you can use immediately.

Bookmark this page - it's your go-to reference for Linux command line operations in 2026.

File and Directory Commands

These are the most frequently used commands for navigating and managing files on any Linux system.

Key Examples

# List all files including hidden, with details
ls -la

# Create nested directories
mkdir -p /var/www/mysite/public/assets

# Copy directory recursively
cp -r /var/www/mysite/ /var/www/mysite-backup/

# Find files modified in the last 24 hours
find /var/log/ -name "*.log" -mtime -1

# Find and delete files older than 30 days
find /tmp/ -type f -mtime +30 -delete

File Content and Text Commands

Commands for viewing, searching, and manipulating file contents - essential for reading logs and configuration files.

Powerful Grep Examples

# Search for errors in all log files
grep -r "error" /var/log/ --include="*.log"

# Case-insensitive search with line numbers
grep -in "failed" /var/log/auth.log

# Show lines before and after match (context)
grep -C 3 "502 Bad Gateway" /var/log/nginx/error.log

# Count occurrences
grep -c "404" /var/log/nginx/access.log

# Exclude patterns
grep -v "bot" access.log | grep "404"

Real-Time Log Monitoring

# Follow log in real time
tail -f /var/log/nginx/access.log

# Follow multiple logs
tail -f /var/log/nginx/access.log /var/log/nginx/error.log

# Follow with grep filter
tail -f /var/log/nginx/access.log | grep "500"

User and Permission Commands

Permission Reference

# Permission numbers explained:
# 7 = read (4) + write (2) + execute (1) = rwx
# 6 = read (4) + write (2) = rw-
# 5 = read (4) + execute (1) = r-x
# 4 = read only = r--
# 0 = no permissions = ---

# Common permission patterns:
chmod 755 directory/    # Owner: rwx, Group: r-x, Others: r-x
chmod 644 file.html     # Owner: rw-, Group: r--, Others: r--
chmod 600 .env          # Owner: rw-, Group: ---, Others: ---
chmod +x script.sh      # Add execute permission for everyone

System Information Commands

Quick Server Health Check

# One-liner server health check
echo "=== CPU ===" && uptime && echo "=== Memory ===" && free -h && echo "=== Disk ===" && df -h / && echo "=== Load ===" && cat /proc/loadavg

Network Commands

Useful Networking Examples

# Check which ports are open and listening
ss -tulnp

# Test if a specific port is open
curl -v telnet://localhost:3000

# Download a file and show progress
wget --progress=bar https://example.com/large-file.tar.gz

# Check HTTP response headers
curl -I https://yourdomain.com

# Sync files to remote server (deploy)
rsync -avz --delete ./dist/ user@server:/var/www/mysite/

Process Management

Essential systemctl Commands

# Manage services
sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl restart nginx
sudo systemctl reload nginx
sudo systemctl status nginx

# Enable/disable on boot
sudo systemctl enable nginx
sudo systemctl disable nginx

# View all running services
systemctl list-units --type=service --state=running

# View service logs
journalctl -u nginx --since "1 hour ago"
journalctl -u nginx -f  # Follow in real time

Cron Job Schedule Format

# Cron format: minute hour day month weekday command
# ┌───────────── minute (0-59)
# │ ┌───────────── hour (0-23)
# │ │ ┌───────────── day of month (1-31)
# │ │ │ ┌───────────── month (1-12)
# │ │ │ │ ┌───────────── day of week (0-6, Sunday=0)
# * * * * * command

# Examples:
0 2 * * * /usr/local/bin/backup.sh          # Daily at 2:00 AM
*/5 * * * * /usr/local/bin/health-check.sh   # Every 5 minutes
0 0 * * 0 certbot renew                      # Weekly on Sunday midnight
0 */6 * * * /usr/bin/apt update              # Every 6 hours

Package Management

APT (Ubuntu/Debian)

# Update package lists
sudo apt update

# Upgrade all packages
sudo apt upgrade -y

# Install a package
sudo apt install nginx -y

# Remove a package
sudo apt remove nginx

# Remove package and config files
sudo apt purge nginx

# Search for packages
apt search nodejs

# Show package info
apt show nginx

# Clean up unused packages
sudo apt autoremove -y

Snap Packages

# Install a snap package
sudo snap install node --classic

# List installed snaps
snap list

# Update all snaps
sudo snap refresh

Disk and Storage Commands

Find Large Files and Directories

# Find top 10 largest files
find / -type f -exec du -h {} + 2>/dev/null | sort -rh | head -10

# Find top 10 largest directories
du -h --max-depth=1 / 2>/dev/null | sort -rh | head -10

# Check disk usage by directory
du -sh /var/* | sort -rh

# Find files larger than 100MB
find / -type f -size +100M -exec ls -lh {} \;

VPS Management Commands

These commands are specifically useful for managing VPS servers day-to-day. For a complete deployment guide, see our website deployment tutorial.

Nginx Management

# Test configuration
sudo nginx -t

# Reload without downtime
sudo systemctl reload nginx

# View access logs
tail -f /var/log/nginx/access.log

# View error logs
tail -f /var/log/nginx/error.log

# List enabled sites
ls -la /etc/nginx/sites-enabled/

Firewall (UFW)

# Check status
sudo ufw status verbose

# Allow a port
sudo ufw allow 8080

# Allow specific IP
sudo ufw allow from 192.168.1.100

# Deny a port
sudo ufw deny 3306

# Delete a rule
sudo ufw delete allow 8080

# Reset all rules
sudo ufw reset

SSL Certificate Management

# Install Certbot
sudo apt install certbot python3-certbot-nginx -y

# Get SSL certificate
sudo certbot --nginx -d yourdomain.com -d www.yourdomain.com

# Renew all certificates
sudo certbot renew

# Check certificate status
sudo certbot certificates

# Test auto-renewal
sudo certbot renew --dry-run

Server Backup

# Full website backup
tar -czf /backups/website-$(date +%Y%m%d).tar.gz /var/www/

# Database backup (MySQL)
mysqldump -u root -p mydb > /backups/db-$(date +%Y%m%d).sql

# Database backup (PostgreSQL)
pg_dump mydb > /backups/db-$(date +%Y%m%d).sql

# Sync backup to remote server
rsync -avz /backups/ user@backup-server:/backups/

Frequently Asked Questions

Conclusion

This Linux commands cheat sheet covers the 100 most essential commands you'll need for daily server management. Bookmark this page and refer back to it whenever you need a quick reference.

Remember: you don't need to memorize every command. Tools like VPS Commander can handle most server management tasks through a visual interface. But knowing these commands gives you the power to handle any situation that comes up.