Hardware · Networking
CLI
Also known as: Command Line Interface, Command Prompt, Terminal, Shell
A CLI (Command Line Interface) is a text-based interface for operating a computer or network device by typing commands, as opposed to using a graphical interface. SSH, terminal, and switch console access all use a CLI.
A CLI accepts typed commands and returns text output. No mouse, no icons — just a prompt waiting for input. This feels primitive compared to a graphical interface, but CLIs offer precision and efficiency that GUIs rarely match for technical work.
Why CLIs matter for IT infrastructure:
Scripting and automation — CLI commands can be scripted, piped, and chained. A task that requires clicking through 50 GUI screens can be a single command or script.
Remote access — SSH gives you full CLI access to a remote server or switch over an encrypted connection, with no graphical overhead.
Consistency — CLI behavior is stable across software versions; GUI layouts change. Documentation, knowledge base articles, and configuration guides for network equipment are almost always written in CLI commands.
Network devices — switches, routers, and firewalls are primarily configured via CLI. Even equipment with web interfaces often lacks full feature parity with the CLI; complex configurations require the command line.
Common CLIs: Bash/Zsh (Linux/macOS), PowerShell and cmd.exe (Windows), Cisco IOS, Juniper Junos, Aruba AOS.