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Command-Line Interface (CLI) ○꠹|Definition|1st|20251122124053-00-⌔
Command-line interface - Wikipedia
Command-line interface
A command-line interface (CLI), also known as a command-line shell,12 is a means of interacting with software via commands – each formatted as a line of text. The concept of interacting with a computer via text evolved over two decades, transitioning from physical hardware to sophisticated software. Before the CLI, computers were programmed using physical switches or punched cards.3 The shift toward a “command” style interaction began with the use of Teleprinters (Teletypes). Early systems like the Whirlwind I (1951) at MIT began utilizing typewriter-like inputs for direct control, moving away from batch processing where you’d hand a stack of cards to an operator and wait hours for a result.4 Devices like the Teletype Model 33, introduced in 1963, allowed operators to type a command and receive a printed response from the computer.5
The command-line interpreter emerged when computers became powerful enough to handle multiple users at once, known as Time-Sharing. The Compatible Time-Sharing System (CTSS), developed in 1961 at MIT, introduced the first true command-line interpreter. For the first time, a user could type a command like LOGIN or PRINT, and a dedicated program (the supervisor) would parse that text and execute the corresponding function. In 1964, Louis Pouzin introduced the software we now recognize as a “shell” for the Multics operating system, providing a programmable environment for executing scripts. Many operating system and software development utilities provide CLI.
A CLI enables automating programs since commands can be stored in a script file that can be used repeatedly. A script allows its contained commands to be executed as a group (as a single program).
Alternatives to a CLI include a GUI (including the desktop metaphor such as Windows), text-based menuing (including DOS Shell and IBM AIX SMIT), and keyboard shortcuts.
Printed 2026-06-28.
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Link to original Footnotes
“Command Line Shell For SQLite”. Archived from the original on 2022-10-06. Retrieved 2025-07-09. ↩
“CAS - Configuring Commandline Shell”. ↩
“The evolution of command line interface (CLI): A historical insight | Contentstack”. www.contentstack.com. Archived from the original on 2025-02-12. Retrieved 2025-01-28. ↩
“July 4: MIT’s Whirlwind Allows Keyboard Input to the Machine | This Day in History | Computer History Museum”. www.computerhistory.org. Retrieved 2026-05-21. ↩
Edwards, Benj (2021-05-17). “What Are Teletypes, and Why Were They Used with Computers?”. How-To Geek. Retrieved 2026-05-21. ↩
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