Linux CheatSheet for common tasks

1. File and Directory Management

ls -lah            # List files with details (including hidden)
cd /path/to/dir    # Change directory
pwd                # Show current directory
mkdir newdir       # Create a directory
rmdir emptydir     # Remove empty directory
rm -rf dir_or_file # Remove file or directory forcefully
cp file1 file2     # Copy file
mv file1 file2     # Move/rename file
find /path -name "*.txt"  # Find files by name

---

2. File Viewing & Editing

cat file.txt       # Show file content
tac file.txt       # Show file content in reverse
head -n 10 file    # Show first 10 lines
tail -n 10 file    # Show last 10 lines
nano file.txt      # Edit file in Nano
vim file.txt       # Edit file in Vim
less file.txt      # View file with scrolling
grep "pattern" file.txt  # Search for a pattern

---

3. User Management

whoami            # Show current user
who              # Show logged-in users
sudo useradd newuser   # Create a new user
sudo passwd newuser    # Set password for user
sudo userdel -r newuser  # Delete user and home directory
sudo groupadd newgroup  # Create a new group
sudo usermod -aG group user  # Add user to group

---

4. Process Management

ps aux            # List running processes
top               # Interactive process viewer
htop              # Better interactive process viewer (install required)
kill -9 PID       # Kill a process by PID
pkill -9 name     # Kill process by name
jobs              # List background jobs
fg %1             # Bring job 1 to foreground
bg %1             # Resume job 1 in background

---

5. Disk & Storage

df -h             # Show disk usage
du -sh folder     # Show folder size
lsblk             # List block devices (disks)
mount /dev/sdX /mnt  # Mount a drive
umount /mnt       # Unmount a drive
fdisk -l          # Show partition table

---

6. Network

ip a              # Show IP addresses
ping google.com   # Test network connectivity
netstat -tulnp    # Show open ports
ss -tulnp         # Show listening ports (better)
wget URL          # Download a file
curl -O URL       # Download file with curl
scp file user@server:/path  # Secure copy file to remote server

---

7. Permissions

chmod 755 file    # Set file permissions (owner: rwx, group: r-x, others: r-x)
chown user:file file.txt  # Change file owner
chgrp group file  # Change file group
ls -l             # View permissions
umask 022         # Set default permissions

---

8. Archiving & Compression

tar -cvf archive.tar file  # Create a tar archive
tar -xvf archive.tar       # Extract a tar archive
tar -czvf archive.tar.gz file  # Create a gzip-compressed tar archive
tar -xzvf archive.tar.gz       # Extract a gzip-compressed tar archive
zip archive.zip file1 file2  # Create zip file
unzip archive.zip           # Extract zip file

---

9. System Monitoring

uptime            # Show system uptime
free -h           # Show memory usage
vmstat 1 5        # Show CPU and memory usage every second for 5 times
iostat            # Show CPU and disk I/O usage
dmesg | tail      # Show kernel logs

---

10. Package Management

Ubuntu/Debian

sudo apt update && sudo apt upgrade  # Update & upgrade packages
sudo apt install package             # Install a package
sudo apt remove package              # Remove a package

CentOS/RHEL

sudo yum update && sudo yum upgrade  # Update & upgrade packages
sudo yum install package             # Install a package
sudo yum remove package              # Remove a package

Arch Linux

sudo pacman -Syu                     # Update system
sudo pacman -S package               # Install package

---

11. Service Management (systemd)

systemctl start service # Start a service
systemctl stop service # Stop a service
systemctl restart service # Restart a service
systemctl enable service # Enable service at boot
systemctl disable service # Disable service