Skip to main content

Linux Basics

This guide provides a brief introduction to Linux, including basic commands and concepts.

  • Change a directory: cd <directory>
  • List files in a directory: ls
  • List files in a directory (including hidden files): ls -a
  • Getting the current directory: pwd
  • Going back a directory: cd ..

Managing Files and Directories​

  • Create a new directory: mkdir <directory>
  • Create a new file: touch <file>
  • Copy a file: cp <file> <new-file>
  • Remove a file: rm <file>
  • Remove a directory: rm -r <directory>

File Permissions​

  • Change file permissions: chmod <permissions> <file>
  • Change file ownership: chown <user> <file>
  • Change file ownership (recursively): chown -R <user> <directory>
  • View file permissions: ls -l <file>

Text Processing​

There are alternatives to nano, but it is the easiest to use.

  • Edit a file: nano <file>
  • View a file: cat <file>
  • View a file (with line numbers): cat -n <file>
  • Get the beginning of a file: head <file>
  • Get the end of a file: tail <file>

File Compression and Archiving​

  • Create a tar archive: tar -cvf <archive.tar> <file>
  • Extract a tar archive: tar -xvf <archive.tar>
  • Create a zip archive: zip <archive.zip> <file>
  • Extract a zip archive: unzip <archive.zip>

Package Management (Ubuntu)​

  • Update package lists: sudo apt update
  • Install a package: sudo apt install <package>
  • Purge a package: sudo apt purge <package>
  • Remove a package: sudo apt remove <package>
  • Search for a package: apt search <package>
  • Upgrade packages: sudo apt upgrade

Networking​

  • Get all interface ips: ip a
  • Ping a host: ping <host>
  • Get the public IP: curl ifconfig.me
  • Get the public IP (alternative): curl ipinfo.io/ip

Firewall (UFW)​

Make sure to allow SSH before enabling the firewall, otherwise you will be locked out of your server. sudo ufw allow ssh

  • Enable the firewall: sudo ufw enable
  • Disable the firewall: sudo ufw disable
  • List all rules: sudo ufw status
  • List all rules (showing numbers): sudo ufw status numbered
  • Delete a rule: sudo ufw delete <rule>
  • Allow a port: sudo ufw allow <port>
  • Deny a port: sudo ufw deny <port>
  • Allow a service: sudo ufw allow <service>
  • Deny a service: sudo ufw deny <service>

Service Management (Systemd)​

  • Start a service: sudo systemctl start <service>
  • Stop a service: sudo systemctl stop <service>
  • Check the status of a service: sudo systemctl status <service>
  • Restart a service: sudo systemctl restart <service>
  • Enable a service (start on boot): sudo systemctl enable <service>
  • Disable a service (stop on boot): sudo systemctl disable <service>
  • Reload a service: sudo systemctl reload <service>