Building CLI Applications

Overview

CLI apps are filters in a pipeline. They read input, transform it, write output. The Unix philosophy applies: do one thing well, compose with others.

When to Use CLI vs TUI vs GUI

digraph decision {
    rankdir=TB;
    "User interaction needed?" [shape=diamond];
    "Complex state/navigation?" [shape=diamond];
    "Scriptable/automatable?" [shape=diamond];
    "CLI" [shape=box, style=filled, fillcolor=lightblue];
    "TUI" [shape=box, style=filled, fillcolor=lightgreen];
    "GUI" [shape=box, style=filled, fillcolor=lightyellow];