Programs: shell libraries

Bash doesn't exactly have libraries per se, but there are some bash-front ends to libraries (like curses) that allow you to interact with them from shellscripts.

UI

dialog (shell)	bash interface for the curses library
bash-oo-framework	OOP, exceptions, etc in bash
tput	get info from the termcap db

Structured Text

jq	parse json
yq	parse yaml
tomlq	parse toml