Command line interface
Definition
A Command Line Interface (CLI) is a text-based user interface that allows users to interact with a computer system or software by typing commands. Unlike graphical user interfaces that rely on icons and menus, a CLI accepts text input and provides text-based output. It is widely used by developers, system administrators, and advanced users for efficient control of operating systems, applications, and servers.
A CLI provides direct access to functions and configurations that may not be available through graphical tools. It enables faster execution of tasks such as file manipulation, network configuration, software installation, and process management. CLIs are often built into operating systems like Linux, Windows, and macOS, as well as cloud platforms and development environments.
Advanced
From a technical perspective, a CLI interprets user commands through a command-line interpreter or shell. Common shells include Bash, Zsh, and PowerShell. Commands often follow a syntax structure that includes the command name, options, and arguments. Scripts can be written to automate repetitive tasks, making the CLI a powerful tool for scalability and efficiency.
Advanced use cases involve managing remote servers, executing API calls, controlling cloud infrastructure through tools such as AWS CLI or Azure CLI, and integrating with CI/CD pipelines. CLIs often support piping and chaining of commands, allowing complex operations to be executed in a single line.
Why it matters
Use cases
Metrics
Issues
Example
A DevOps engineer uses the AWS CLI to deploy infrastructure in multiple regions. Instead of clicking through a web console, the engineer executes a single script that provisions servers, configures networking, and deploys applications. This saves time, reduces human error, and ensures consistency across environments.