Override help print message?

[LoganSutherland]

Is it possible to override the --help/-h message created by CLI with my own print message?

[phlptp]

The simplest way to do that is clear the help_flap

app->set_help_flag("");

then you can create your own option

app->add_flag_callback("--help",[](){ <print whatever you want here>;  throw CLI::Success;})->trigger_on_parse();

A more complicated flexible way is to customize the formatter

/// Set the help formatter
    App *formatter(std::shared_ptr<FormatterBase> fmt) {
        formatter_ = fmt;
        return this;
    }

    /// Set the help formatter
    App *formatter_fn(std::function<std::string(const App *, std::string, AppFormatMode)> fmt) {
        formatter_ = std::make_shared<FormatterLambda>(fmt);
        return this;
    }