node-helmsman 

Easily make command line interfaces using git style subcommand executables


So what does helmsman actually do?

A common setup for command line applications is
(for example: git commit -m 'message'). Rather than
having a giant file that switches or if elses over each potential
subcommand, it's much neater to store each subcommand in it's own file
(bin/command,bin/command-subcomand, bin/command-subcommand2, etc).
Helmsman makes it easy to add, modify or delete subcommands without having to
do housekeeping steps in your root command file or package.json

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* Helmsman is automatically aware of all the - files in
your modules bin/ (or any folder you tell it to look at)
* --help automatically generates help output, telling you all the
subcommands that are available to you
* --version prints the version from package.json of the module
requiring helmsman
* Running automatically executes the
- file, passing along all the arguments & options
* Helmsman is capable of smart command completion including dynamic shorthands
and spelling correction (eg: st => status or
isntall => install )
* Use whatever option parsing library you want for your subcommands
(optimist,
commander, etc)
* Helmsman is minimally intrusive in your
subcommands

Installation & Setup

In your command line application folder:

``
npm install helmsman --save
`

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In your main executable, add helmsman:

`javascript
#!/usr/bin/env node

var helmsman = require('helmsman');

helmsman().parse();
`

Want to append in additional help messaging or modify the arguments that are
parsed?

`javascript
#!/usr/bin/env node

var helmsman = require('helmsman');

var cli = helmsman()

cli.on('--help', function(){
console.log('EXTRA HELPFUL!');
});

var argv = process.argv;

argv.push('--pizza');

// parse() can accept modified arguments, otherwise it defaults to process.argv
cli.parse(argv);
`

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For your sub-executables to work with helmsman you need to do two things: 1.
Expose metadata about the task, like its description and 2. Make sure the meat
& potatoes of the script only runs when it's directly called

`javascript
#!/usr/bin/env node

// 1. Expose the metadata
exports.command = {
description: 'Show current worker counts and their pids'
};

// 2. Make sure it only runs when it's directly called:
if (require.main === module) {
// Parse options and run the magic
}
`

Note: If you're not putting each script in package.json's bin object,
make sure that the sub-commands are executable by running chmod +x
bin/-

API

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* options {Object}

Create an instance of helmsman. It is an EventEmitter and will also begin
searching for files once it's instantiated.

#### Events

* --help: Emitted when --help is passed as the first option or no commands
or options are passed

#### Options

* localDir: The local module folder where to search for executable files.
Defaults to the directory of the executable (eg: If you execute
/bin/ the localDir will be /bin)
* prefix: The prefix of the subcommands to search for. Defaults to the
executed file (eg: If you run it will search for files in the
localDir that start with -
* metadata: An object containing keys of command names and sub-objects
containing the keys description and optionally arguments
* usePath: If true helmsman will search the PATH for commands matching the
prefix
* fillCommandData: An optional function to use to retrieve metadata from a
command file; takes a defaults object, a filename, and an extension
* fallbackCommandData: If true helmsman will use its default function to
retrieve metadata from a command file if the user-specified fuction returns
a falsy value
* ignoreRequireFail: If true helmsman will ignore failures to require an
extensionless or .js-extensioned command file
* nodePath: The path to the node executable on Windows, defaults to 'node'

#### Methods

* parse([argv]) Parse argv or process.argv if there is no argv and either
display the help or run the subcommand

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* description: A one line description of the command. Required.
* arguments: A shorthand for options the subcommand accepts. Generated help
will include it next to command. See help "

TODO

* Allow for automatically including npm installed
libraries

Thanks

Much of this was inspired by TJ Holowaychuk's
commander and
component