`ArgumentParser/ParsableCommand`

ParsableCommand types are the basic building blocks for command-line tools built using ArgumentParser. To create a command, declare properties using the @Argument, @Option, and @Flag property wrappers, or include groups of options with @OptionGroup. Finally, implement your command's functionality in the run()-7p2fr method.

@main
struct Repeat: ParsableCommand {
    @Argument(help: "The phrase to repeat.")
    var phrase: String

    @Option(help: "The number of times to repeat 'phrase'.")
    var count: Int? = nil

    mutating func run() throws {
        let repeatCount = count ?? 2
        for _ in 0..<repeatCount {
            print(phrase)
        }
    }
}

Note: The Swift compiler uses either the type marked with @main or a main.swift file as the entry point for an executable program. You can use either one, but not both — rename your main.swift file to the name of the command when you add @main.

Topics

Essentials

Implementing a Command's Behavior

run()-7p2fr
ParsableArguments/validate()-5r0ge

Customizing a Command

configuration-35km1
CommandConfiguration

Generating Help Text

helpMessage(for:includeHidden:columns:)

Starting the Program

main()
main(_:)

Manually Parsing Input

parseAsRoot(_:)

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ArgumentParser/ParsableCommand