This can be done with the action attribute. If your field is a bool then by default the action selected is ArgAction::SetTrue. This is quite nice since you don’t need to set a value when you call the argument. It sets the value by default to true if used and false if not used when … Read more
Based on the official clap documentation. Modified by wrapping the Subcommand in Option, which makes it optional: use clap::{Parser, Subcommand}; #[derive(Parser)] #[command(author, version, about, long_about = None)] #[command(propagate_version = true)] struct Cli { #[command(subcommand)] command: Option<Commands>, } #[derive(Subcommand)] enum Commands { /// Adds files to myapp Add { name: Option<String> }, } fn main() { … Read more
Use clap::AppSettings::ArgRequiredElseHelp: App::new(“myprog”) .setting(AppSettings::ArgRequiredElseHelp) See also: Method call on clap::App moving ownership more than once