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    5.2.1 • Public • Published

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    A mature, feature-complete library to parse command-line options.


    You can set options using the main notation standards (learn more). These commands are all equivalent, setting the same values:

    $ example --verbose --timeout=1000 --src one.js --src two.js
    $ example --verbose --timeout 1000 --src one.js two.js
    $ example -vt 1000 --src one.js two.js
    $ example -vt 1000 one.js two.js

    To access the values, first create a list of option definitions describing the options your application accepts. The type property is a setter function (the value supplied is passed through this), giving you full control over the value received.

    const optionDefinitions = [
      { name: 'verbose', alias: 'v', type: Boolean },
      { name: 'src', type: String, multiple: true, defaultOption: true },
      { name: 'timeout', alias: 't', type: Number }

    Next, parse the options using commandLineArgs():

    const commandLineArgs = require('command-line-args')
    const options = commandLineArgs(optionDefinitions)

    options now looks like this:

      src: [
      verbose: true,
      timeout: 1000

    Advanced usage

    Beside the above typical usage, you can configure command-line-args to accept more advanced syntax forms.

    • Command-based syntax (git style) in the form:

      $ executable <command> [options]

      For example.

      $ git commit --squash -m "This is my commit message"
    • Command and sub-command syntax (docker style) in the form:

      $ executable <command> [options] <sub-command> [options]

      For example.

      $ docker run --detached --image centos bash -c yum install -y httpd

    Usage guide generation

    A usage guide (typically printed when --help is set) can be generated using command-line-usage. See the examples below and read the documentation for instructions how to create them.

    A typical usage guide example.


    The polymer-cli usage guide is a good real-life example.


    Further Reading

    There is plenty more to learn, please see the wiki for examples and documentation.


    $ npm install command-line-args --save

    © 2014-22 Lloyd Brookes <>. Documented by jsdoc-to-markdown.


    npm i command-line-args

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