Unfortunately, there’s no association between -input and sunrise.CR2 or between -output and sunrise.JPG. NET Core Executable” for alternative command-line syntax), the imageconv program will launch into the Main entry point, static void Main(string args), with a string array of four corresponding arguments. Given this command line (see “Passing Parameters to the. The command line could be something like this: imageconv -input sunrise.CR2 -output sunrise.JPG Imagine that you’re writing an image conversion program that converts an image file to a different format based on the output name specified. With this in mind, System.CommandLine was developed and released in alpha form (see /dotnet/command-line-api). NET includes numerous attempts at solving this problem, none has emerged as a default solution, and none scales well to support both simple and complex scenarios. Prior to System.CommandLine, the lack of built-in parsing support meant that when your application launched, you as the developer had to analyze the array of arguments to determine which corresponded to which argument type, and then correctly associate all of the values together. For example, with dotnet, “classlib” is an alias for “Class library” and -v is an alias for “-verbosity.” For example, when specifying the verbosity of a dotnet build, you can use any of the following three variations: -verbosity=diagnostic, -verbosity diagnostic or -verbosity:diagnostic.Īliases: These are additional names that can be used to identify commands and options. Common delimiters are space, colon and the equal sign. Because directives are part of the System.CommandLine framework, they’re included automatically, without any effort on the part of the command-line interface developer.ĭelimiters: The association of an argument to a command or an option is done via a delimiter. For example, a redirect command can force all output (stderr and stdout) to go into an. The value associated with a command or option is called the argument.ĭirectives: These are commands that are cross-cutting for all applications. Again, with dotnet new, the -name option has an argument for specifying the name of the project. Similarly, options may have values associated with them. This value is required when you specify the new command. For example, the dotnet new command includes the template name. As the name implies, options are generally not a required element of a command.Īrguments: Both commands and options can have associated values. ![]() For example, the dotnet build command includes the -no-restore option, which you can specify to disable the restore command from running implicitly (and instead relying on prior execution of the restore command). Options: These provide a way to modify the behavior of a command. For instance, the command “dotnet add package” has “dotnet” as the root command, “add” as a subcommand and “package” as the subcommand to add (perhaps call it the sub-subcommand?). Subcommands to the root command-the name of the executable itself (for example, git.exe)-may themselves have their own subcommands. Technically, the commands specified after the executable name are, in fact, subcommands. Some of the built-in commands for git are branch, add, status, commit and push. Here’s a description of each construct:Ĭommands: These are the actions that are supported by the application command line. The constructs supported include commands, options, arguments, directives, delimiters and aliases. Invokes functionality that’s configured to execute based on the command-line value. ![]() (Technically, command-line hosts allow for the combining of words into a single token using quotes.) Enables parsing of command-line generic arguments (tokens) into distinct constructs, where each word on the command line is a token. ![]()
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