Running scripts with ruby command - Step-by-Step Execution

Concept Flow - Running scripts with ruby command

Write Ruby script file

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Open terminal/command line

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Type: ruby filename.rb

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Ruby interpreter reads file

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Execute code line by line

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Output results to terminal

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Script ends

This flow shows how you write a Ruby script, run it using the ruby command in the terminal, and see the output.

Execution Sample

Ruby

puts "Hello, Ruby!"
puts 2 + 3

This script prints a greeting and the result of 2 plus 3.

Execution Table

Step	Action	Code Executed	Output
1	Start script execution	puts "Hello, Ruby!"	Hello, Ruby!
2	Execute next line	puts 2 + 3	5
3	End of script	No more lines	Script ends

💡 Reached end of file, script stops

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
No variables	-	-	-	-

Key Moments - 3 Insights

Why do I need to type 'ruby filename.rb' in the terminal?

Typing 'ruby filename.rb' tells the computer to use the Ruby interpreter to read and run your script file, as shown in execution_table step 1.

What happens if I run 'ruby' without a filename?

Without a filename, Ruby opens an interactive prompt instead of running a script file, so no script lines execute as in execution_table.

Why does the output appear in the terminal?

The 'puts' command prints text to the terminal, so each executed line outputs immediately, as seen in execution_table steps 1 and 2.

Visual Quiz - 3 Questions

Look at the execution table, what is the output after step 2?

A 2 + 3

B Hello, Ruby!

C 5

D No output

💡 Hint

Check the 'Output' column in row for step 2 in execution_table

At which step does the script finish running?

A Step 3

B Step 2

C Step 1

D Never finishes

💡 Hint

Look at the 'Action' column in execution_table where it says 'End of script'

If you add 'puts "Bye!"' after line 2, what will happen in the execution table?

A The output '5' will change to 'Bye!'

B A new step will show output 'Bye!' after step 2

C The script will stop before printing 'Bye!'

D No change in output

💡 Hint

Adding a line adds a new step with its output, similar to steps 1 and 2

Concept Snapshot

Run Ruby scripts by typing 'ruby filename.rb' in terminal
Ruby reads and runs the file line by line
Output from 'puts' shows in terminal
Script ends when file ends
No special setup needed for simple scripts

Full Transcript

To run a Ruby script, first write your code in a file with .rb extension. Then open your terminal or command line. Type 'ruby' followed by your file name, like 'ruby script.rb'. The Ruby interpreter reads your file and runs each line in order. Commands like 'puts' print output to the terminal immediately. When the interpreter reaches the end of the file, the script stops running. This process lets you see your program's results right away.