💻 What is CLI (Command Line Interface)?
🧩 The Context:
CLI was the primary way users interacted with computers before GUIs (Graphical User Interfaces) became mainstream. It’s still used heavily by developers, system administrators, and in automation.
🧾 Definition:
A Command Line Interface (CLI) is a text-based interface that allows users to interact with the operating system or software by typing commands into a terminal or shell.
🧱 How it Works:
-
You open a terminal or shell (like
bash,cmd, orPowerShell). -
You type a command (e.g.,
ls,cd,mkdir,ping, etc.). -
The OS parses the command, executes it, and shows output.
It’s non-graphical, fast, and precise, but has a steeper learning curve.
🎯 Examples of CLI Commands:
| OS Type | Example CLI |
|---|---|
| Linux/Unix | ls -l, cd, sudo apt update |
| Windows | dir, cd, ipconfig |
| Mac | same as Unix-based (bash/zsh commands) |
🔑 Advantages:
-
Lightweight (no need for graphics)
-
Fast for repetitive and automated tasks
-
Scriptable (can use shell scripts for automation)
⚠️ Disadvantages:
-
Not beginner-friendly
-
You need to remember commands and syntax
-
Errors can be destructive if you’re not careful (
rm -rf /😬)
🖥️ CLI vs GUI:
| CLI | GUI |
|---|---|
| Text-based | Graphical (icons, windows) |
| Fast and powerful | User-friendly |
| Harder to learn | Easier for beginners |
| Easier to automate | Hard to automate |
🧠 Interview Line:
“CLI is a text-based interface that lets users interact with the OS by typing commands—preferred for its speed, precision, and automation capabilities.”