Linux Common Commands

2024-02-20

File Commands

  • ls # Directory listing
  • ls -l # Long listing format
  • ls -a # List all files including hidden files
  • cd /path/to/directory # Change directory
  • pwd # Display the current working directory
  • mkdir directory_name # Create a new directory
  • rmdir directory_name # Remove an empty directory
  • rm file_name # Remove a file
  • rm -r directory_name # Remove a directory and its contents recursively
  • touch file_name # Create or update a file
  • cat file_name # Concatenate and display the file content
  • more file_name # View file content page by page
  • less file_name # Improved viewing of file content over 'more'
  • cp source_file target_file # Copy files from source to target
  • mv old_name new_name # Rename or move a file/directory

SSH (Secure Shell)

  • ssh user@host # Connect to host as user
  • ssh -p port user@host # Connect using a specific port
  • ssh-keygen -t rsa # Generate rsa key pair
  • ssh-copy-id user@host # Copy your key to the remote server for password-less login
  • grep pattern files # Search for pattern in files
  • grep -r pattern dir # Recursively search for pattern in dir
  • find /dir -name name* # Find files starting with name in dir
  • locate file_name # Find files by name (uses a database)

Process Management

  • ps # Display your currently active processes
  • ps aux | grep process_name # Find process named process_name
  • top # Display all running processes
  • kill pid # Kill process with given pid
  • killall process_name # Kill all processes named process_name
  • bg # List stopped or background jobs; resume a stopped job in the background
  • fg # Brings the most recent job to foreground

File Permissions

  • chmod +x file_name # Make file executable
  • chmod 755 file_name # Set read and execute permissions for owner and read for others
  • chown user:group file_name # Change file owner and group

Network

  • ifconfig # Display all network interfaces and ip address
  • ping host # Send ICMP echo request to host
  • traceroute host # Display the route packets take to network host
  • netstat -tulnp # Display listening ports and their applications

Archive and Compression

  • tar cf archive_name.tar files # Create a tar named archive_name.tar containing files
  • tar xf archive_name.tar # Extract the files from archive_name.tar
  • gzip file_name # Compresses file and renames it to file.gz
  • gunzip file.gz # Decompresses file.gz back to original

System Info and Management

  • uname -a # Show system and kernel info
  • df -h # Display free disk space in human-readable form
  • du -sh directory_name # Show disk usage of directory in human-readable form
  • free -m # Show free and used memory in MB

Package Management (Debian/Ubuntu)

  • sudo apt-get update # Update package list index
  • sudo apt-get upgrade # Upgrade all packages
  • sudo apt-get install package_name # Install package

Package Management (Rhat/CentOS) and both dnf and yum is available, and dnf is newer and better.

  • sudo dnf/yum check-update # Update package list index
  • sudo dnf/yum upgrade # Upgrade all packages
  • sudo dnf/yum install package_name # Install a package
  • sudo dnf/yum remove package_name # Remove a package
  • sudo dnf/yum search package_name # Search for a package
  • sudo dnf/yum list installed # List installed packages

Text editors

  • nano file_name # Open file in nano editor
  • vi file_name # Open file in vi editor

MISC Commands

  • man command_name # Show manual for command
  • echo "text" # Display message on screen
  • date # Display current date and time
  • uptime # Show how long the system has been running
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