Starship is a program that provides a colorful customizable prompt for your favorite shell. Development happens as open source over at https://github.com/starship/starship. Both the shells that I use, fish and bash, are supported by this tool!
$ curl -sS https://starship.rs/install.sh | sh
# ~/.config/fish/config.fish starship init fish | source
# ~/.bashrc eval "$(starship init bash)"