Catalog
concept#Architecture#Software Engineering#DevOps#Platform

Command Line Interface (CLI)

A text-based interaction model that lets users and scripts control programs and operating systems via commands. CLIs are especially suited for automation, scripting, and precise control.

Command-line interfaces (CLIs) are text-based user interfaces that allow users and scripts to interact with programs and systems via commands.
Established
Medium

Classification

  • Medium
  • Technical
  • Architectural
  • Intermediate

Technical context

CI/CD systems (e.g. Jenkins, GitHub Actions)Configuration management (e.g. Ansible via CLI)Scripting runtimes (e.g. Bash, PowerShell, Python)

Principles & goals

Precision over discovery: commands should be deterministic and predictable.Scriptability: interfaces must be easily automatable.Consistency: uniform parameter and exit-code conventions foster integration.
Build
Team, Domain

Use cases & scenarios

Compromises

  • Faulty scripts can cause data loss or downtime.
  • Insecure defaults or missing permissions increase abuse risk.
  • Fragmentation due to varying implementations and flags.
  • Use clear, documented parameters and subcommands.
  • Provide machine-readable outputs (JSON) for integrations.
  • Design idempotent commands and meaningful exit codes.

I/O & resources

  • Command documentation and manpages
  • Access to a shell or console environment
  • Scriptable tools and libraries
  • Executable scripts and automations
  • Logs, reports and exit codes
  • Reproducible operational states

Description

Command-line interfaces (CLIs) are text-based user interfaces that allow users and scripts to interact with programs and systems via commands. They provide efficient automation, fine-grained control, and low overhead. CLIs trade graphical discoverability for speed, scriptability, and reproducible workflows.

✔

  • High efficiency for experienced users and automation.
  • Low resource usage and simple remote control.
  • Easy integration into CI/CD pipelines and scripts.

✖

  • Limited discoverability for new users.
  • Platform dependencies in shell behavior and paths.
  • Complex commands can be hard to document and maintain.

  • Automation ratio

    Share of repeatable tasks automated via CLI scripts.

  • Mean Time to Recovery (MTTR) using CLI

    Average time to resolve incidents using CLI interventions.

  • Script reusability

    Proportion of reusable script modules versus ad-hoc scripts.

Linux shell (Bash) for server administration

Bash provides typical CLI commands and scripting capability for administration tasks.

Git CLI for version control

Git offers a text-based interface to control versioning and workflows.

Docker CLI for container management

Docker CLI enables creation, management, and orchestration of containers via commands.

1

Requirement analysis: identify tasks to be supported by CLI.

2

Design: define consistent command, parameter and exit-code conventions.

3

Implementation: develop, document and test commands and scripts.

4

Integration: integrate CLI into CI/CD and monitoring.

5

Operation: ensure training, permission management and versioning.

⚠️ Technical debt & bottlenecks

  • Unrefactored legacy scripts without tests.
  • Ad-hoc utilities without central documentation.
  • Dependency on deprecated shell features or tools.
Platform differences in shell behaviorInconsistent exit codes or error outputLack of documentation for complex commands
  • Using CLI commands with root privileges for routine tasks without checks.
  • Hardcoded paths and environment variables in scripts.
  • Untested mass operations on production data via CLI.
  • Assumptions about shell behavior across platforms lead to errors.
  • Missing return values and logging hinder error diagnosis.
  • Too restrictive permissions prevent necessary automations.
Basic shell scripting skillsUnderstanding of exit codes and streamsKnowledge of automation and CI principles
Automatability of workflowsPortability across operating systemsSecurity and least-privilege principle
  • • Different shells and versions on target systems
  • • Restricted user privileges for remote access
  • • Need for POSIX or platform-specific adjustments