# Examples
See the [Example Folder](/example) for more demonstrations of
Yargs in the wild. We would love fixes to old examples and pull
requests for fancy new examples, [help contribute!](https://github.com/yargs/yargs/blob/master/contributing.md).
With yargs, the options be just a hash!
-------------------------------------------------------------------
plunder.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2)).argv;
if (argv.ships > 3 && argv.distance < 53.5) {
console.log('Plunder more riffiwobbles!');
} else {
console.log('Retreat from the xupptumblers!');
}
```
***
$ ./plunder.js --ships=4 --distance=22
Plunder more riffiwobbles!
$ ./plunder.js --ships 12 --distance 98.7
Retreat from the xupptumblers!
But don't walk the plank just yet! There be more! You can do short options:
-------------------------------------------------
short.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2)).argv;
console.log('(%d,%d)', argv.x, argv.y);
```
***
$ ./short.js -x 10 -y 21
(10,21)
And booleans, both long, short, and even grouped:
----------------------------------
bool.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2)).argv;
if (argv.s) {
process.stdout.write(argv.fr ? 'Le perroquet dit: ' : 'The parrot says: ');
}
console.log(
(argv.fr ? 'couac' : 'squawk') + (argv.p ? '!' : '')
);
```
***
$ ./bool.js -s
The parrot says: squawk
$ ./bool.js -sp
The parrot says: squawk!
$ ./bool.js -sp --fr
Le perroquet dit: couac!
And non-hyphenated options too! Just use `argv._`!
-------------------------------------------------
nonopt.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2)).argv;
console.log('(%d,%d)', argv.x, argv.y);
console.log(argv._);
```
***
$ ./nonopt.js -x 6.82 -y 3.35 rum
(6.82,3.35)
[ 'rum' ]
$ ./nonopt.js "me hearties" -x 0.54 yo -y 1.12 ho
(0.54,1.12)
[ 'me hearties', 'yo', 'ho' ]
Yargs even counts your booleans!
----------------------------------------------------------------------
count.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.count('verbose')
.alias('v', 'verbose')
.argv;
VERBOSE_LEVEL = argv.verbose;
function WARN() { VERBOSE_LEVEL >= 0 && console.log.apply(console, arguments); }
function INFO() { VERBOSE_LEVEL >= 1 && console.log.apply(console, arguments); }
function DEBUG() { VERBOSE_LEVEL >= 2 && console.log.apply(console, arguments); }
WARN("Showing only important stuff");
INFO("Showing semi-important stuff too");
DEBUG("Extra chatty mode");
```
***
$ node count.js
Showing only important stuff
$ node count.js -v
Showing only important stuff
Showing semi-important stuff too
$ node count.js -vv
Showing only important stuff
Showing semi-important stuff too
Extra chatty mode
$ node count.js -v --verbose
Showing only important stuff
Showing semi-important stuff too
Extra chatty mode
Tell users how to use your options and make demands.
-------------------------------------------------
area.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.usage('Usage: $0 -w [num] -h [num]')
.demandOption(['w','h'])
.argv;
console.log("The area is:", argv.w * argv.h);
```
***
$ ./area.js -w 55 -h 11
The area is: 605
$ node ./area.js -w 4.91 -w 2.51
Usage: area.js -w [num] -h [num]
Options:
-w [required]
-h [required]
Missing required arguments: h
After your demands have been met, demand more! Ask for non-hyphenated arguments!
-----------------------------------------
demand_count.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.demandCommand(2)
.argv;
console.dir(argv);
```
***
$ ./demand_count.js a
Not enough non-option arguments: got 1, need at least 2
$ ./demand_count.js a b
{ _: [ 'a', 'b' ], '$0': 'demand_count.js' }
$ ./demand_count.js a b c
{ _: [ 'a', 'b', 'c' ], '$0': 'demand_count.js' }
EVEN MORE SHIVER ME TIMBERS!
------------------
default_singles.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.default('x', 10)
.default('y', 10)
.argv
;
console.log(argv.x + argv.y);
```
***
$ ./default_singles.js -x 5
15
default_hash.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.default({ x : 10, y : 10 })
.argv
;
console.log(argv.x + argv.y);
```
***
$ ./default_hash.js -y 7
17
And if you really want to get all descriptive about it...
---------------------------------------------------------
boolean_single.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.boolean(['r','v'])
.argv
;
console.dir([ argv.r, argv.v ]);
console.dir(argv._);
```
***
$ ./boolean_single.js -r false -v "me hearties" yo ho
[ false, true ]
[ 'me hearties', 'yo', 'ho' ]
boolean_double.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.boolean(['x','y','z'])
.argv
;
console.dir([ argv.x, argv.y, argv.z ]);
console.dir(argv._);
```
***
$ ./boolean_double.js -x -z one two three
[ true, undefined, true ]
[ 'one', 'two', 'three' ]
Yargs is here to help you...
---------------------------
You can describe parameters for help messages and set aliases. Yargs figures
out how to format a handy help string automatically.
line_count.js:
```javascript
#!/usr/bin/env node
var argv = require('yargs/yargs')(process.argv.slice(2))
.usage('Usage: $0 <command> [options]')
.command('count', 'Count the lines in a file')
.example('$0 count -f foo.js', 'count the lines in the given file')
.alias('f', 'file')
.nargs('f', 1)
.describe('f', 'Load a file')
.demandOption(['f'])
.help('h')
.alias('h', 'help')
.epilog('copyright 2019')
.argv;
var fs = require('fs');
var s = fs.createReadStream(argv.file);
var lines = 0;
s.on('data', function (buf) {
lines += buf.toString().match(/\n/g).length;
});
s.on('end', function () {
console.log(lines);
});
```
***
$ node line_count.js
Usage: line_count.js <command> [options]
Commands:
line_count.js count Count the lines in a file
Options:
--version Show version number [boolean]
-f, --file Load a file [required]
-h, --help Show help [boolean]
Examples:
line_count.js count -f foo.js count the lines in the given file
copyright 2019
Missing required argument: f
$ node line_count.js count
line_count.js count
Count the lines in a file
Options:
--version Show version number [boolean]
-f, --file Load a file [required]
-h, --help Show help [boolean]
Missing required argument: f
$ node line_count.js count --file line_count.js
25
$ node line_count.js count -f line_count.js
25
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