changes to tools:
- output less noise that drowns the signal. The toolchain used to build a program from source is particularly problematic here.
- if the output has to be huge, make it structured / collapsible
- output messages that are both human-readable (so humans don't have to read cryptic data that is meant for the computer) and computer-readable (so the computer does not have to parse human-readable messages, which is fragile). Yes, that's hard.
- Provides tools that each solves one problem, and solves it well.
Some things that could have been changes to tools are implemented by tool-specific extensions (IIRC, bash autocomplete of tool parameters works like this). Discoverability can to some extent be implemented like that, including inconsistent naming of command-line options for different tools.
Might require changes to the kernel (details depend on the OS, and on whether the terminal runs inside a GUI window):
- proper handling of color. Right now, color is encoded as in-band information (ANSI escape sequences) that confuse various tools, e.g. grep cannot find a substring if there is a color change in the middle of a substring. The workaround is to have all tools detect if they write to the terminal or a pipe and not output color at all, which means that I can't grep without losing color. This might require changing the kernel because the terminal driver that defines how color is encoded sits there (again, might be different in a terminal window in the GUI).
(edit: formatting)