How to invoke the Ruby Interpreter

Invoking the Ruby Interpreter

The following is the command-line syntax for executing the typical C-based Ruby implementation:

ruby [options] [--] program [arguments]

Options include none, one, or many command-line arguments that modify how the interpreter behaves.

The file with the Ruby program to be run is called program. If the program's name begins with a hyphen, put -- before it to ensure it's considered a program name rather than an option.

Any additional tokens on the command line are known as arguments. These tokens become the ARGV array's elements.

Common Options

The options that the typical C-based Ruby implementation supports are listed below. You may have to set the RUBYOPT environment variable to include any of the -W, -w, -v, -d, -I, -r, -K, -E, and -T options. Every time the interpreter is invoked, these will automatically be used as if they were specified on the command line.

-w

This setting activates warnings for incorrect or deprecated code. Programmers frequently use this option to check that their code is clean.

-e script

This option executes the Ruby script. The interpreter does not load or run any programs supplied on the command line if one or more -e options are specified.

-I path

This option adds the directories in the path to the beginning of the global $LOAD PATH array. This lists the directories that the load and require methods should search.

-r library

Before starting the specified program, this option loads the library selected.

-rubygems

This widely used command-line argument is merely a creative usage of the -r option and not a genuine option. The standard library's ubygems module is loaded. Ruby 1.8 is the only version required for this option because Ruby 1.9 can load installed gems without this module.

–disable-gems

This option in Ruby 1.9 stops the default load path from expanding to include gem installation folders. If you have a lot of installed gems but are running a program that doesn't use any of them, you might find that using this option speeds up program startup.

-d, --debug

The global variables $DEBUG and $VERBOSE are set to true by these options. When these variables are set, your program or the library code that your application uses could print debugging output or take other actions.

-h

This option displays a list of interpreter choices.

Warnings and Information Options

-W, -W2, --verbose

These options are equivalent to -w, enabling verbose warnings and setting $VERBOSE to true.

-Wo 

This option disables all warnings.

-v

This option displays the version number of Ruby.

Miscellaneous Options

-c

This option analyzes the program and highlights any syntax mistakes; it does not execute it.

-C dir, -X dir

Before running the program, these choices switch the current directory to dir.

-s

The interpreter preprocesses arguments that follow the program name and starts with a hyphen when this option is used.

-x [dir] 

By removing all lines before the first that begin with #!ruby, this option extracts the Ruby source from the program file. This option additionally permits the specification of a directory for compatibility with the capital -X option.

Frequently Asked Questions

What is a Ruby interpreter?

Any program that interprets Ruby source code is called a Ruby interpreter.

The most popular Ruby interpreters are YARV, Ruby MRI/CRuby, JRuby, and Rubinius.

What is Ruby spec suite?

The Ruby Spec Suite is a collection of tests designed to ensure that a particular Ruby implementation produces the expected behavior and results when interpreting a program. It ensures the interpreters are all reliable, experienced choices for running Ruby code because they have all passed the Ruby Spec Suite.

How can we invoke the Ruby interpreter in the command line?

The command-line syntax for executing the typical C-based Ruby implementation is: ruby [options] [--] program [arguments]

What is -rubygem option in a ruby interpreter?

This widely used command-line argument is merely a creative usage of the -r option and not a genuine option. The standard library's ubygems module is loaded. Ruby 1.8 is the only version required for this option because Ruby 1.9 can load installed gems without this module.

Which interpreter should we use?

You almost definitely use YARV (if Ruby 1.9 and higher) or Ruby MRI (if Ruby 1.8 and below) if you installed the default version of Ruby. For Ruby developers, this default option is generally sufficient.

Conclusion

In this article, we have learned about Ruby's command-line options, including the most common, warning, and miscellaneous options. All of these flags can be useful; give them a try! 

After learning how to invoke the ruby interpreter, are you curious to explore more articles on the topic related to the Ruby programming language? We have you covered. Check out Ruby, Ruby-Coding Ninjas Blog from Coding Ninjas. You can also refer to the official ruby website and check out Documentation, Official ruby FAQ, and Ruby Koans.

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Happy learning!