Bash, Zsh, sh, tcsh, and the TUI tools built on top of them - prompts, scripting, multiplexers, and terminal troubleshooting.
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.
Installing Starship, a fast, shell-agnostic prompt that works identically across Bash, Zsh, and fish, and configuring which information it shows.
Running multiple shell sessions inside one terminal window, splitting panes, and, most importantly, keeping sessions alive across disconnects.
Setting up a terminal-based file manager for navigating, previewing, and manipulating files entirely with the keyboard, without leaving the terminal.
Installing and configuring a full-screen terminal system monitor for real-time CPU, memory, and process information, entirely keyboard-driven.
Setting up Windows Terminal specifically for a smooth WSL experience: default profile, font, and the settings that most commonly need adjusting.
Installing Zsh as your shell, setting up Oh My Zsh, and configuring a theme and a first useful plugin, from a default shell to a productive one.