$ fish -c "[command]"
$ fish [path/to/script.fish]
$ fish --no-execute [path/to/script.fish]
Start an interactive shell session in private mode, where the shell does not access old history or save new history
$ fish --private
$ fish --version
Set and export environmental variables that persist across shell restarts (from within the shell only)
$ set -Ux [variable_name] [variable_value]