Running scripts with ruby command - Cheat Sheet & Quick Revision

Recall & Review

beginner

How do you run a Ruby script named hello.rb from the command line?

You run it by typing ruby hello.rb in the terminal and pressing Enter.

beginner

What does the ruby command do when running a script?

It starts the Ruby interpreter, reads the script file, and executes the Ruby code inside it.

intermediate

Can you run a Ruby script without the ruby command? If yes, how?

Yes, by adding a shebang line #!/usr/bin/env ruby at the top of the script and making it executable with chmod +x script.rb, then run it with ./script.rb.

beginner

What happens if you run ruby without any script file?

Ruby starts an interactive session called IRB (Interactive Ruby), where you can type Ruby code and see results immediately.

intermediate

How do you pass arguments to a Ruby script when running it?

You add the arguments after the script name like ruby script.rb arg1 arg2. Inside the script, you access them with the ARGV array.

What command runs a Ruby script named app.rb?

A run app.rb

B ruby app.rb

C execute app.rb

D start app.rb

The correct command to run a Ruby script is ruby app.rb.

What does the ARGV array contain in a Ruby script?

A The script's filename

B Environment variables

C Ruby interpreter version

D Command line arguments passed to the script

ARGV holds the command line arguments passed to the Ruby script.

How can you make a Ruby script executable without typing ruby before it?

A Add <code>#!/usr/bin/env ruby</code> at the top and make it executable

B Rename it to <code>.exe</code>

C Use <code>chmod 000</code>

D Run it with <code>run script.rb</code>

Adding a shebang line and making the script executable allows running it directly.

What happens if you type ruby alone in the terminal?

A It runs the last script

B It shows an error

C It opens an interactive Ruby session

D It exits immediately

Typing ruby alone starts IRB, an interactive Ruby shell.

Which of these is NOT a way to run a Ruby script?

A run script.rb

B ./script.rb (with shebang and executable permission)

C ruby script.rb

D Using IRB to load the script

run script.rb is not a valid command to run Ruby scripts.

Explain how to run a Ruby script from the command line and how to pass arguments to it.

Think about the command format and how the script receives extra words after the filename.

Describe how to make a Ruby script executable without typing 'ruby' before it.

Consider what goes at the top of the file and what permission you change.