[Animats]

This is a classic problem with open-source GUIs - they're a wrapper around a command-line program. Such programs typically have no clue what happened at the command line level - they just present whatever the command line program prints to the user.

A few days ago, there was a UI designer on here who was looking for an open source program to work on. I suggested "git gui". Git's default GUI is a Tk wrapper around the command line program. Lots of buttons, corresponding to command line options. No understanding at the GUI level of what's safe, what's useful right now, and what the state of the project is.

The original Macintosh deliberately lacked a command line, so programmers had to figure out a usable GUI for everything. They had the right idea.

One of the original design misfeatures of UNIX is that programs take in command line parameters and environment variables, but all they give back is a numeric error code. If they gave back a list of strings and a set of name/value pairs, and there was some convention about what should come back, scripts and GUI front ends would be less dumb.

[hossbeast]

They also write a descriptive message (and nothing else) on stderr as a convention.

[Animats]

Which is usually useless to a GUI or a script.

[hossbeast]

Other than for informing the user what went wrong (which is specifically one of the things you called out as a problem)