Essential Linux Commands for VPS Users

  # List files (with details and hidden files)
ls -la

# Change directory
cd /var/www/html
cd ~                  # go to home directory
cd ..                 # go up one level

# Create directories
mkdir mysite
mkdir -p /var/www/mysite/public_html   # create nested directories

# Copy files and folders
cp file.txt backup.txt
cp -r /var/www/site1 /var/www/site1-backup   # copy directory recursively

# Move / rename
mv oldname.txt newname.txt
mv /tmp/file.txt /var/www/html/

# Delete
rm file.txt
rm -rf directory/     # delete directory and everything inside (careful!)

# Find files
find / -name "php.ini"                    # search entire system
find /var/www -name "*.log" -size +100M   # find logs over 100MB
  

  # View file contents
cat file.txt          # print entire file
less file.txt         # scrollable viewer (press q to quit)
head -50 file.txt     # first 50 lines
tail -50 file.txt     # last 50 lines
tail -f /var/log/syslog   # follow log in real time

# Edit files
nano file.txt         # simple editor (Ctrl+O to save, Ctrl+X to exit)
vim file.txt          # powerful editor (press i to insert, Esc then :wq to save and quit)
  

  # View permissions
ls -la file.txt
# Example output: -rw-r--r-- 1 www-data www-data 1234 Apr 1 12:00 file.txt

# Change ownership
chown www-data:www-data file.txt
chown -R www-data:www-data /var/www/html/   # recursive

# Change permissions
chmod 644 file.txt       # owner read/write, group read, others read
chmod 755 directory/     # owner full, group read/execute, others read/execute
chmod -R 755 /var/www/html/

# Common WordPress permissions
find /var/www/html -type d -exec chmod 755 {} \;   # directories
find /var/www/html -type f -exec chmod 644 {} \;   # files
  

  # Overall disk usage
df -h

# Directory sizes
du -sh /var/www/*          # size of each item in /var/www
du -sh /home/*/            # size of each user's home directory

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

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

  # List running processes
ps aux                       # all processes
ps aux | grep nginx          # find specific process
top                          # live process monitor (press q to quit)
htop                         # better version of top (install: apt install htop)

# Kill a process
kill 12345                   # graceful stop (replace with PID)
kill -9 12345                # force kill

# Check what's using a port
ss -tlnp                     # list all listening ports
lsof -i :80                  # what's on port 80?
lsof -i :443                 # what's on port 443?
  

  # System details
uname -a                     # kernel version
lsb_release -a               # Ubuntu/Debian version
cat /etc/os-release          # OS info

# Hardware
nproc                        # number of CPU cores
free -h                      # memory usage
uptime                       # how long the server has been running

# Who's logged in
who
last -10                     # last 10 logins
  

  # Test connectivity
ping -c 4 google.com         # 4 pings to test internet
curl -I https://yourdomain.com   # check HTTP headers

# DNS lookup
dig yourdomain.com           # full DNS lookup
dig yourdomain.com A         # just A records
dig yourdomain.com MX        # mail records
nslookup yourdomain.com      # simpler DNS lookup

# Download files
wget https://example.com/file.tar.gz
curl -O https://example.com/file.tar.gz

# Check open ports
ss -tlnp                     # TCP listening ports
ufw status                   # firewall rules (if using UFW)
  

  # Check service status
systemctl status nginx
systemctl status mysql

# Start / stop / restart
sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl restart nginx
sudo systemctl reload nginx    # reload config without downtime

# Enable/disable on boot
sudo systemctl enable nginx    # start on boot
sudo systemctl disable nginx   # don't start on boot

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

  # Update package lists
sudo apt update

# Upgrade installed packages
sudo apt upgrade -y

# Install a package
sudo apt install htop

# Remove a package
sudo apt remove htop
sudo apt autoremove            # clean up unused dependencies

# Search for packages
apt search package-name
  

  # Create a tar.gz archive
tar -czf backup.tar.gz /var/www/html/

# Extract a tar.gz archive
tar -xzf backup.tar.gz

# Create a zip
zip -r backup.zip /var/www/html/

# Extract a zip
unzip backup.zip

# List contents without extracting
tar -tzf backup.tar.gz
  

  # Edit your crontab
crontab -e

# Cron format: minute hour day month weekday command
# Examples:
# Run every 5 minutes
*/5 * * * * /path/to/script.sh

# Run daily at 3:00 AM
0 3 * * * /usr/bin/certbot renew

# Run every Sunday at midnight
0 0 * * 0 /root/backup.sh

# List current cron jobs
crontab -l
  

  # Check who's hitting your web server the most
awk '{print $1}' /var/log/nginx/access.log | sort | uniq -c | sort -rn | head -20

# Find and kill a process by name
pkill -f "process-name"

# Watch a command output refresh every 2 seconds
watch -n 2 'df -h'

# Quick backup with timestamp
cp file.txt file.txt.$(date +%Y%m%d-%H%M%S)