[zawerf]

The problem is that CLIs are undiscoverable. You either know what `ls` is or it's just a bunch of random letters. Your average user will never learn a new unforgiving language just to talk to their computer.

You can try to re-experience that frustration for yourself by playing an interactive fiction text adventure game. For example in http://adamcadre.ac/if/905.html, the first few things I tried were: "left", "go left", "move left", "map", "where am i", "help", "?", "tell me what I can type", "fuck you", "exit" (you've now exited the room and are in the living room)

[josefx]

Sounds like a lazily written cli, typing help in bash gives usefull information and also refers to info. So you get an overview of the available commands and a description of the basics with minimal effort.

Meanwhile I can play hide and seek with the tools I need in Gimp for hours.

[ProxCoques]

Indeed. What if the cli had both natural language syntax, large alias/synonym matching, and command prediction (eg similar to Gmail's recent feature)? That might reduce the non-discoverability issue to about the same as most direct manipulation ui (where you have to look through menus for the "right" item to click on).

[cgio]

Mathematica has something akin to command prediction and it’s also a very nice way to learn the language.