Step-by-step, task-oriented guides - do this, in this order, to get this result.
Set up RetroArch netplay with matched builds and content, private lobby settings, relay-first connectivity, narrow firewall rules, tested ports, and logs.
Use RetroArch overrides safely by separating frontend settings, core options, input remaps, and shader presets across core, directory, and game scopes.
Install RetroArch and trusted Libretro cores, configure writable data paths, verify firmware and controllers, and prove a clean game launch.
Build a supportable RetroPie console with a model-matched official image, secure networking, lawful content, safe updates, and tested backups.
Configure RetroArch rewind with verified save-state support, measured memory and frame-time costs, safe hotkeys, narrow overrides, and rollback tests.
Configure RetroArch run-ahead from measured internal game lag, validate core serialization and performance, and keep a reversible per-game profile.
The two essential shell debugging tools: one traces exactly what a script actually executes, the other catches whole categories of bugs before it ever runs.
Setting up fzf, a general-purpose fuzzy finder that plugs into history search, file finding, and practically any list-based shell workflow.
Writing shell scripts that run correctly under any POSIX-compliant shell, not just whichever one happens to be installed on your own machine.
GNU screen is older and less feature-rich than tmux, but still genuinely useful, and often already pre-installed on systems where tmux isn't.