# Using the command line

CasperJS ships with a built-in command line parser on top of PhantomJS’ parser, located in the `cli` module. It exposes passed arguments as positional ones and named options

A `Casper` instance always contains a ready-to-use `cli` property for easy access to these parameters, so you don’t have to worry about manipulating the `cli` module parsing API.

Let’s consider this simple casper script:

    var casper = require("casper").create();

    casper.echo("Casper CLI passed args:");
    require("utils").dump(casper.cli.args);

    casper.echo("Casper CLI passed options:");
    require("utils").dump(casper.cli.options);

    casper.exit();

Note

Please note the two `casper-path` and `cli` options; these are passed to the casper script through the `casperjs` Python executable.

Execution results:

    $ casperjs test.js arg1 arg2 arg3 --foo=bar --plop anotherarg
    Casper CLI passed args: [
        "arg1",
        "arg2",
        "arg3",
        "anotherarg"
    ]
    Casper CLI passed options: {
        "casper-path": "/Users/niko/Sites/casperjs",
        "cli": true,
        "foo": "bar",
        "plop": true
    }

Getting, checking or dropping parameters:

    var casper = require("casper").create();
    casper.echo(casper.cli.has(0));
    casper.echo(casper.cli.get(0));
    casper.echo(casper.cli.has(3));
    casper.echo(casper.cli.get(3));
    casper.echo(casper.cli.has("foo"));
    casper.echo(casper.cli.get("foo"));
    casper.cli.drop("foo");
    casper.echo(casper.cli.has("foo"));
    casper.echo(casper.cli.get("foo"));
    casper.exit();

Execution results:

    $ casperjs test.js arg1 arg2 arg3 --foo=bar --plop anotherarg
    true
    arg1
    true
    anotherarg
    true
    bar
    false
    undefined

Hint

You may need to wrap an option containing a space with escaped double quotes in Windows. –foo=\”space bar\”

Hint

What if you want to check if any arg or option has been passed to your script? Here you go:

    // removing default options passed by the Python executable
    casper.cli.drop("cli");
    casper.cli.drop("casper-path");

    if (casper.cli.args.length === 0 && Object.keys(casper.cli.options).length === 0) {
        casper.echo("No arg nor option passed").exit();
    }

## casperjs native options

New in version 1.1.

The casperjs command has three available options:

- `--direct`: to print out log messages to the console
- `--log-level=[debug|info|warning|error]` to set the logging level
- `--engine=[phantomjs|slimerjs]` to select the browser engine you want to use. CasperJS supports PhantomJS (default) that runs Webkit, and SlimerJS that runs Gecko.

Warning

Deprecated since version 1.1.

The `--direct` option has been renamed to `--verbose`. Although `--direct` will still work, it is now considered deprecated.

Example:

    $ casperjs --verbose --log-level=debug myscript.js

Last but not least, you can still use all PhantomJS standard CLI options as you would do with any other PhantomJS script:

    $ casperjs --web-security=no --cookies-file=/tmp/mycookies.txt myscript.js

Hint

To remember what the native PhantomJS cli options are available, run the `phantomjs --help` command. SlimerJS supports almost same options as PhantomJS.

## Raw parameter values

New in version 1.0.

By default, the cli object will process every passed argument & cast them to the appropriate detected type; example script:

    var casper = require('casper').create();
    var utils = require('utils');

    utils.dump(casper.cli.get('foo'));

    casper.exit();

If you run this script:

    $ casperjs c.js --foo=01234567
    1234567

As you can see, the `01234567` value has been cast to a Number.

If you want the original string, use the `raw` property of the `cli` object, which contains the raw values of the passed parameters:

    var casper = require('casper').create();
    var utils = require('utils');

    utils.dump(casper.cli.get('foo'));
    utils.dump(casper.cli.raw.get('foo'));

    casper.exit();

Sample usage:

    $ casperjs c.js --foo=01234567
    1234567
    "01234567"

For very long numbers, use the `raw` property as there is an ECMA script limitation with a numeric precision of up to 17 places. More info here - https://github.com/casperjs/casperjs/issues/1134