Basic Terminal Commands

Linux is more powerful in a CLI (command input) environment than in a GUI (mouse click) environment.

1. File and Directory Management

• pwd: Print current directory path (Print Working Directory)
• ls: List files and folders in the current directory (-al option recommended)
• cd [path]: Change directory (cd .. to move to the parent directory)
• mkdir [name]: Create a new directory (folder)
• rm [name]: Delete file (rm -rf forcefully deletes a folder, so be careful)
• cp [source] [target]: Copy file/folder
• mv [source] [target]: Move file/folder or rename

2. Checking and Editing File Content

• cat [file]: Print the entire contents of a file
• head/tail [file]: Print the beginning/end of a file (tail -f is useful for checking logs in real-time)
• grep [string] [file]: Search for a specific string within a file
• vi or vim: Standard Linux text editor (Exit: :q, Save and exit: :wq)
• nano: A text editor that is easy for beginners to use

3. Network and System Information

• top / htop: Check real-time system resource (CPU, memory) usage
• df -h: Check disk free space
• free -m: Check memory usage
• ip addr: Check network interface information such as IP address
• ping [address]: Check network connection status

4. Package Management (Ubuntu based)

• sudo apt update: Update package lists
• sudo apt install [package]: Install a program
• sudo apt upgrade: Update all package versions

In the next section, we'll learn about the file permission system, which is the security model of Linux.