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https://github.com/actions/setup-python.git
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513 lines
10 KiB
Markdown
513 lines
10 KiB
Markdown
# DEPRECATION NOTICE
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I don't want to maintain this module anymore since I just use
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[minimist](https://npmjs.org/package/minimist), the argument parsing engine,
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directly instead nowadays.
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See [yargs](https://github.com/chevex/yargs) for the modern, pirate-themed
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successor to optimist.
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[![yarrrrrrrgs!](http://i.imgur.com/4WFGVJ9.png)](https://github.com/chevex/yargs)
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You should also consider [nomnom](https://github.com/harthur/nomnom).
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optimist
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========
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Optimist is a node.js library for option parsing for people who hate option
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parsing. More specifically, this module is for people who like all the --bells
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and -whistlz of program usage but think optstrings are a waste of time.
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With optimist, option parsing doesn't have to suck (as much).
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[![build status](https://secure.travis-ci.org/substack/node-optimist.png)](http://travis-ci.org/substack/node-optimist)
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examples
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========
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With Optimist, the options are just a hash! No optstrings attached.
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-------------------------------------------------------------------
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xup.js:
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist').argv;
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if (argv.rif - 5 * argv.xup > 7.138) {
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console.log('Buy more riffiwobbles');
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}
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else {
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console.log('Sell the xupptumblers');
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}
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````
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***
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$ ./xup.js --rif=55 --xup=9.52
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Buy more riffiwobbles
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$ ./xup.js --rif 12 --xup 8.1
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Sell the xupptumblers
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![This one's optimistic.](http://substack.net/images/optimistic.png)
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But wait! There's more! You can do short options:
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-------------------------------------------------
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short.js:
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist').argv;
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console.log('(%d,%d)', argv.x, argv.y);
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````
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***
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$ ./short.js -x 10 -y 21
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(10,21)
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And booleans, both long and short (and grouped):
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----------------------------------
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bool.js:
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````javascript
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#!/usr/bin/env node
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var util = require('util');
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var argv = require('optimist').argv;
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if (argv.s) {
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util.print(argv.fr ? 'Le chat dit: ' : 'The cat says: ');
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}
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console.log(
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(argv.fr ? 'miaou' : 'meow') + (argv.p ? '.' : '')
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);
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````
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***
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$ ./bool.js -s
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The cat says: meow
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$ ./bool.js -sp
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The cat says: meow.
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$ ./bool.js -sp --fr
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Le chat dit: miaou.
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And non-hypenated options too! Just use `argv._`!
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-------------------------------------------------
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nonopt.js:
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist').argv;
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console.log('(%d,%d)', argv.x, argv.y);
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console.log(argv._);
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````
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***
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$ ./nonopt.js -x 6.82 -y 3.35 moo
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(6.82,3.35)
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[ 'moo' ]
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$ ./nonopt.js foo -x 0.54 bar -y 1.12 baz
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(0.54,1.12)
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[ 'foo', 'bar', 'baz' ]
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Plus, Optimist comes with .usage() and .demand()!
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-------------------------------------------------
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divide.js:
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist')
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.usage('Usage: $0 -x [num] -y [num]')
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.demand(['x','y'])
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.argv;
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console.log(argv.x / argv.y);
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````
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***
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$ ./divide.js -x 55 -y 11
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5
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$ node ./divide.js -x 4.91 -z 2.51
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Usage: node ./divide.js -x [num] -y [num]
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Options:
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-x [required]
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-y [required]
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Missing required arguments: y
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EVEN MORE HOLY COW
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------------------
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default_singles.js:
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist')
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.default('x', 10)
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.default('y', 10)
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.argv
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;
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console.log(argv.x + argv.y);
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````
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***
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$ ./default_singles.js -x 5
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15
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default_hash.js:
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist')
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.default({ x : 10, y : 10 })
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.argv
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;
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console.log(argv.x + argv.y);
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````
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***
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$ ./default_hash.js -y 7
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17
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And if you really want to get all descriptive about it...
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---------------------------------------------------------
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boolean_single.js
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist')
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.boolean('v')
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.argv
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;
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console.dir(argv);
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````
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***
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$ ./boolean_single.js -v foo bar baz
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true
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[ 'bar', 'baz', 'foo' ]
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boolean_double.js
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist')
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.boolean(['x','y','z'])
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.argv
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;
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console.dir([ argv.x, argv.y, argv.z ]);
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console.dir(argv._);
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````
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***
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$ ./boolean_double.js -x -z one two three
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[ true, false, true ]
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[ 'one', 'two', 'three' ]
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Optimist is here to help...
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---------------------------
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You can describe parameters for help messages and set aliases. Optimist figures
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out how to format a handy help string automatically.
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line_count.js
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````javascript
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#!/usr/bin/env node
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var argv = require('optimist')
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.usage('Count the lines in a file.\nUsage: $0')
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.demand('f')
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.alias('f', 'file')
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.describe('f', 'Load a file')
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.argv
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;
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var fs = require('fs');
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var s = fs.createReadStream(argv.file);
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var lines = 0;
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s.on('data', function (buf) {
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lines += buf.toString().match(/\n/g).length;
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});
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s.on('end', function () {
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console.log(lines);
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});
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````
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***
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$ node line_count.js
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Count the lines in a file.
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Usage: node ./line_count.js
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Options:
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-f, --file Load a file [required]
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Missing required arguments: f
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$ node line_count.js --file line_count.js
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20
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$ node line_count.js -f line_count.js
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20
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methods
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=======
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By itself,
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````javascript
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require('optimist').argv
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`````
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will use `process.argv` array to construct the `argv` object.
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You can pass in the `process.argv` yourself:
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````javascript
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require('optimist')([ '-x', '1', '-y', '2' ]).argv
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````
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or use .parse() to do the same thing:
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````javascript
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require('optimist').parse([ '-x', '1', '-y', '2' ])
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````
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The rest of these methods below come in just before the terminating `.argv`.
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.alias(key, alias)
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------------------
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Set key names as equivalent such that updates to a key will propagate to aliases
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and vice-versa.
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Optionally `.alias()` can take an object that maps keys to aliases.
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.default(key, value)
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--------------------
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Set `argv[key]` to `value` if no option was specified on `process.argv`.
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Optionally `.default()` can take an object that maps keys to default values.
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.demand(key)
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------------
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If `key` is a string, show the usage information and exit if `key` wasn't
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specified in `process.argv`.
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If `key` is a number, demand at least as many non-option arguments, which show
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up in `argv._`.
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If `key` is an Array, demand each element.
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.describe(key, desc)
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--------------------
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Describe a `key` for the generated usage information.
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Optionally `.describe()` can take an object that maps keys to descriptions.
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.options(key, opt)
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------------------
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Instead of chaining together `.alias().demand().default()`, you can specify
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keys in `opt` for each of the chainable methods.
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For example:
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````javascript
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var argv = require('optimist')
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.options('f', {
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alias : 'file',
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default : '/etc/passwd',
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})
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.argv
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;
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````
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is the same as
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````javascript
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var argv = require('optimist')
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.alias('f', 'file')
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.default('f', '/etc/passwd')
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.argv
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;
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````
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Optionally `.options()` can take an object that maps keys to `opt` parameters.
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.usage(message)
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---------------
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Set a usage message to show which commands to use. Inside `message`, the string
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`$0` will get interpolated to the current script name or node command for the
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present script similar to how `$0` works in bash or perl.
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.check(fn)
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----------
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Check that certain conditions are met in the provided arguments.
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If `fn` throws or returns `false`, show the thrown error, usage information, and
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exit.
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.boolean(key)
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-------------
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Interpret `key` as a boolean. If a non-flag option follows `key` in
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`process.argv`, that string won't get set as the value of `key`.
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If `key` never shows up as a flag in `process.arguments`, `argv[key]` will be
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`false`.
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If `key` is an Array, interpret all the elements as booleans.
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.string(key)
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------------
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Tell the parser logic not to interpret `key` as a number or boolean.
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This can be useful if you need to preserve leading zeros in an input.
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If `key` is an Array, interpret all the elements as strings.
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.wrap(columns)
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--------------
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Format usage output to wrap at `columns` many columns.
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.help()
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-------
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Return the generated usage string.
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.showHelp(fn=console.error)
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---------------------------
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Print the usage data using `fn` for printing.
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.parse(args)
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------------
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Parse `args` instead of `process.argv`. Returns the `argv` object.
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.argv
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-----
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Get the arguments as a plain old object.
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Arguments without a corresponding flag show up in the `argv._` array.
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The script name or node command is available at `argv.$0` similarly to how `$0`
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works in bash or perl.
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parsing tricks
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==============
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stop parsing
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------------
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Use `--` to stop parsing flags and stuff the remainder into `argv._`.
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$ node examples/reflect.js -a 1 -b 2 -- -c 3 -d 4
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{ _: [ '-c', '3', '-d', '4' ],
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'$0': 'node ./examples/reflect.js',
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a: 1,
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b: 2 }
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negate fields
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-------------
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If you want to explicity set a field to false instead of just leaving it
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undefined or to override a default you can do `--no-key`.
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$ node examples/reflect.js -a --no-b
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{ _: [],
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'$0': 'node ./examples/reflect.js',
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a: true,
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b: false }
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numbers
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-------
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Every argument that looks like a number (`!isNaN(Number(arg))`) is converted to
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one. This way you can just `net.createConnection(argv.port)` and you can add
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numbers out of `argv` with `+` without having that mean concatenation,
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which is super frustrating.
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duplicates
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----------
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If you specify a flag multiple times it will get turned into an array containing
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all the values in order.
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$ node examples/reflect.js -x 5 -x 8 -x 0
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{ _: [],
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'$0': 'node ./examples/reflect.js',
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x: [ 5, 8, 0 ] }
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dot notation
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------------
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When you use dots (`.`s) in argument names, an implicit object path is assumed.
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This lets you organize arguments into nested objects.
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$ node examples/reflect.js --foo.bar.baz=33 --foo.quux=5
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{ _: [],
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'$0': 'node ./examples/reflect.js',
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foo: { bar: { baz: 33 }, quux: 5 } }
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short numbers
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-------------
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Short numeric `head -n5` style argument work too:
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$ node reflect.js -n123 -m456
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{ '3': true,
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'6': true,
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_: [],
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'$0': 'node ./reflect.js',
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n: 123,
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m: 456 }
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installation
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============
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With [npm](http://github.com/isaacs/npm), just do:
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npm install optimist
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or clone this project on github:
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git clone http://github.com/substack/node-optimist.git
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To run the tests with [expresso](http://github.com/visionmedia/expresso),
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just do:
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expresso
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inspired By
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===========
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This module is loosely inspired by Perl's
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[Getopt::Casual](http://search.cpan.org/~photo/Getopt-Casual-0.13.1/Casual.pm).
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