# Commander.js


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  The complete solution for [node.js](http://nodejs.org) command-line interfaces, inspired by Ruby's [commander](https://github.com/tj/commander).  
  [API documentation](http://tj.github.com/commander.js/)


## Installation

    $ npm install commander

## Option parsing

 Options with commander are defined with the `.option()` method, also serving as documentation for the options. The example below parses args and options from `process.argv`, leaving remaining args as the `program.args` array which were not consumed by options.

```js
#!/usr/bin/env node

/**
 * Module dependencies.
 */

var program = require('commander');

program
  .version('0.0.1')
  .option('-p, --peppers', 'Add peppers')
  .option('-P, --pineapple', 'Add pineapple')
  .option('-b, --bbq', 'Add bbq sauce')
  .option('-c, --cheese [type]', 'Add the specified type of cheese [marble]', 'marble')
  .parse(process.argv);

console.log('you ordered a pizza with:');
if (program.peppers) console.log('  - peppers');
if (program.pineapple) console.log('  - pineapple');
if (program.bbq) console.log('  - bbq');
console.log('  - %s cheese', program.cheese);
```

 Short flags may be passed as a single arg, for example `-abc` is equivalent to `-a -b -c`. Multi-word options such as "--template-engine" are camel-cased, becoming `program.templateEngine` etc.


## Coercion

```js
function range(val) {
  return val.split('..').map(Number);
}

function list(val) {
  return val.split(',');
}

function collect(val, memo) {
  memo.push(val);
  return memo;
}

function increaseVerbosity(v, total) {
  return total + 1;
}

program
  .version('0.0.1')
  .usage('[options] <file ...>')
  .option('-i, --integer <n>', 'An integer argument', parseInt)
  .option('-f, --float <n>', 'A float argument', parseFloat)
  .option('-r, --range <a>..<b>', 'A range', range)
  .option('-l, --list <items>', 'A list', list)
  .option('-o, --optional [value]', 'An optional value')
  .option('-c, --collect [value]', 'A repeatable value', collect, [])
  .option('-v, --verbose', 'A value that can be increased', increaseVerbosity, 0)
  .parse(process.argv);

console.log(' int: %j', program.integer);
console.log(' float: %j', program.float);
console.log(' optional: %j', program.optional);
program.range = program.range || [];
console.log(' range: %j..%j', program.range[0], program.range[1]);
console.log(' list: %j', program.list);
console.log(' collect: %j', program.collect);
console.log(' verbosity: %j', program.verbose);
console.log(' args: %j', program.args);
```

## Regular Expression
```js
program
  .version('0.0.1')
  .option('-s --size <size>', 'Pizza size', /^(large|medium|small)$/i, 'medium')
  .option('-d --drink [drink]', 'Drink', /^(coke|pepsi|izze)$/i)
  .parse(process.argv);
  
console.log(' size: %j', program.size);
console.log(' drink: %j', program.drink);
```

## Variadic arguments

 The last argument of a command can be variadic, and only the last argument.  To make an argument variadic you have to
 append `...` to the argument name.  Here is an example:

```js
#!/usr/bin/env node

/**
 * Module dependencies.
 */

var program = require('commander');

program
  .version('0.0.1')
  .command('rmdir <dir> [otherDirs...]')
  .action(function (dir, otherDirs) {
    console.log('rmdir %s', dir);
    if (otherDirs) {
      otherDirs.forEach(function (oDir) {
        console.log('rmdir %s', oDir);
      });
    }
  });

program.parse(process.argv);
```

 An `Array` is used for the value of a variadic argument.  This applies to `program.args` as well as the argument passed
 to your action as demonstrated above.

## Git-style sub-commands

```js
// file: ./examples/pm
var program = require('..');

program
  .version('0.0.1')
  .command('install [name]', 'install one or more packages')
  .command('search [query]', 'search with optional query')
  .command('list', 'list packages installed')
  .parse(process.argv);
```

When `.command()` is invoked with a description argument, no `.action(callback)` should be called to handle sub-commands, otherwise there will be an error. This tells commander that you're going to use separate executables for sub-commands, much like `git(1)` and other popular tools.  
The commander will try to search the executables in the directory of the entry script (like `./examples/pm`) with the name `program-command`, like `pm-install`, `pm-search`.

If the program is designed to installed globally, make sure the executables have proper modes, like `755`.

## Automated --help

 The help information is auto-generated based on the information commander already knows about your program, so the following `--help` info is for free:

```  
 $ ./examples/pizza --help

   Usage: pizza [options]

   An application for pizzas ordering

   Options:

     -h, --help           output usage information
     -V, --version        output the version number
     -p, --peppers        Add peppers
     -P, --pineapple      Add pineapple
     -b, --bbq            Add bbq sauce
     -c, --cheese <type>  Add the specified type of cheese [marble]
     -C, --no-cheese      You do not want any cheese

```

## Custom help

 You can display arbitrary `-h, --help` information
 by listening for "--help". Commander will automatically
 exit once you are done so that the remainder of your program
 does not execute causing undesired behaviours, for example
 in the following executable "stuff" will not output when
 `--help` is used.

```js
#!/usr/bin/env node

/**
 * Module dependencies.
 */

var program = require('commander');

program
  .version('0.0.1')
  .option('-f, --foo', 'enable some foo')
  .option('-b, --bar', 'enable some bar')
  .option('-B, --baz', 'enable some baz');

// must be before .parse() since
// node's emit() is immediate

program.on('--help', function(){
  console.log('  Examples:');
  console.log('');
  console.log('    $ custom-help --help');
  console.log('    $ custom-help -h');
  console.log('');
});

program.parse(process.argv);

console.log('stuff');
```

Yields the following help output when `node script-name.js -h` or `node script-name.js --help` are run:

```

Usage: custom-help [options]

Options:

  -h, --help     output usage information
  -V, --version  output the version number
  -f, --foo      enable some foo
  -b, --bar      enable some bar
  -B, --baz      enable some baz

Examples:

  $ custom-help --help
  $ custom-help -h

```

## .outputHelp()

Output help information without exiting.

If you want to display help by default (e.g. if no command was provided), you can use something like:

```js
var program = require('commander');

program
  .version('0.0.1')
  .command('getstream [url]', 'get stream URL')
  .parse(process.argv);

  if (!process.argv.slice(2).length) {
    program.outputHelp();
  }
```

## .help()

  Output help information and exit immediately.

## Examples

```js
var program = require('commander');

program
  .version('0.0.1')
  .option('-C, --chdir <path>', 'change the working directory')
  .option('-c, --config <path>', 'set config path. defaults to ./deploy.conf')
  .option('-T, --no-tests', 'ignore test hook')

program
  .command('setup [env]')
  .description('run setup commands for all envs')
  .option("-s, --setup_mode [mode]", "Which setup mode to use")
  .action(function(env, options){
    var mode = options.setup_mode || "normal";
    env = env || 'all';
    console.log('setup for %s env(s) with %s mode', env, mode);
  });

program
  .command('exec <cmd>')
  .alias('ex')
  .description('execute the given remote cmd')
  .option("-e, --exec_mode <mode>", "Which exec mode to use")
  .action(function(cmd, options){
    console.log('exec "%s" using %s mode', cmd, options.exec_mode);
  }).on('--help', function() {
    console.log('  Examples:');
    console.log();
    console.log('    $ deploy exec sequential');
    console.log('    $ deploy exec async');
    console.log();
  });

program
  .command('*')
  .action(function(env){
    console.log('deploying "%s"', env);
  });

program.parse(process.argv);
```

More Demos can be found in the [examples](https://github.com/tj/commander.js/tree/master/examples) directory.

## License

MIT

