Table of Contents

Arguments

An argument is a value passed to an option or a command. The following examples show an argument for the verbosity option and an argument for the build command.

dotnet tool update dotnet-suggest --verbosity quiet --global
                                              ^---^

dotnet build myapp.csproj
             ^----------^

Arguments can have default values that apply if no argument is explicitly provided. For example, many options are implicitly Boolean parameters with a default of true when the option name is in the command line. The following command-line examples are equivalent:

dotnet tool update dotnet-suggest --global
                                  ^------^

dotnet tool update dotnet-suggest --global true
                                  ^-----------^

Some options have required arguments. For example in the .NET CLI, --output requires a folder name argument. If the argument is not provided, the command fails.

Arguments can have expected types, and System.CommandLine displays an error message if an argument can't be parsed into the expected type. For example, the following command errors because "silent" isn't one of the valid values for --verbosity:

dotnet build --verbosity silent

Cannot parse argument 'silent' for option '-v' as expected type 'Microsoft.DotNet.Cli.VerbosityOptions'. Did you mean one of the following?
Detailed
Diagnostic
Minimal
Normal
Quiet

The properties for [CliArgument] attribute (see CliArgumentAttribute docs for more info):

  • Name
  • Description
  • Hidden
  • Order
  • HelpName
  • Required
  • Arity
  • AllowedValues
  • ValidationRules
  • ValidationPattern
  • ValidationMessage
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