Top 60 Linux Commands You Need to Know

SSH (Secure Shell)

• Connect to a Linux machine remotely.
• Syntax: ssh [user]@[server].

File and Directory Commands

Listing and Moving Around Directories

• ls: List files in the current directory.
  • ls -l: Detailed list.
  • ls -a: Include hidden files.
• pwd: Print working directory.
• cd [directory]: Change directory.
  • cd ..: Go back one directory level.
  • cd: Go back to home directory.

Creating, Moving, and Deleting Files

• touch [filename]: Create a new file or update the timestamp of an existing file.
• cp [file] [destination]: Copy a file.
• mv [file] [destination]: Move (or rename) a file.
• rm [file]: Delete a file.
• mkdir [directory]: Create a new directory.
• rmdir [directory]: Remove an empty directory.
  • rm -r [directory]: Remove a directory recursively with files.

Viewing and Editing Files

• cat [file]: Display the contents of a file.
• nano [file]: Edit a file with the Nano text editor.
• vim [file]: Edit a file with the Vim text editor.
  • Insert mode: Press i
  • Save and quit: Press Esc, type :wq
• echo [text] > [file]: Write text to a file (overwrites).
• echo [text] >> [file]: Append text to a file.
• shred [file]: Securely delete a file.

Links and Permissions

• ln -s [target] [link]: Create a symbolic link.
• chmod +x [file]: Make a file executable.
• chown [user] [file]: Change the ownership of a file.

Additional Commands

• clear: Clear the terminal screen.
• whoami: Display the current user.
• exit: Exit the terminal or a user session.

User Management

• sudo [command]: Run command with superuser privileges.
• adduser [username]: Create a new user (Debian-based).
• useradd [username]: Add a new user (generic).
• passwd [username]: Change a user's password.
• su [username]: Switch user.
• finger [username]: Display information about a user (requires installation).

Package Management

Installing Software

• Update package list: sudo apt update (Debian-based)
• Install a package: sudo apt install [package] (Debian-based)
• Red Hat-based: yum [command]
• Arch-based: Use corresponding package manager

System Information and Manual Pages

• man [command]: Open the manual for a command.
• what [command]: Brief description of a command.
• which [command]: Locate a command.
• whereis [command]: Locate the binary, source, and manual-page files for a command.
• df -h: Display free space on mounted filesystems.
• uname -a: Print system information.
• neofetch: Display system information in a neat format (requires installation).
• cal: Display a calendar.
• free: Display memory usage.

Downloading Files

• wget [URL]: Download files from the web.
• curl [URL] > [file]: Download files using cURL.

Compression and Decompression

• zip [zipfile] [file(s)]: Create a zip archive.
• unzip [zipfile]: Extract a zip archive.

Viewing File Content

• less [file]: View file content one page at a time.
• head [file]: View the first lines of a file.
• tail [file]: View the last lines of a file.
• cmp [file1] [file2]: Compare two files.
• diff [file1] [file2]: Show differences between two files.
• sort [file]: Sort the lines of a file.
• find [location] -name [filename]: Search for files.

Network Commands

• ipconfig: Display all network interfaces and their IP addresses.
• ping [address]: Check connectivity to a host.
  • ping -c [count] [address]: Limit the number of ping requests.
• traceroute [address]: Display the route packets take to a network host.
• netstat: Display network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.
  • netstat -tuln: Show listening ports.
• ss -tuln: Another way to check for listening ports.
• sudo ufw: Manage the uncomplicated firewall.

Process Management

• ps aux: Display a snapshot of current processes.
• top: Display running system processes and their resource usage.
• htop: An improved version of top (requires installation).
• kill [PID]: Kill a process by its process ID.
  • kill -9 [PID]: Force kill a process.
• pkill [name]: Kill processes by name instead of PID.

System Controls

• sudo systemctl [command] [service]: Control system services.
  • Commands include start, stop, restart, status.
• history: Show command history.
• sudo reboot: Reboot the system.
• sudo shutdown: Shut down the system.