5 Ways to Run System Commands in Ruby

Introduction

Ruby is a versatile programming language that allows developers to interact with the underlying system through system commands. In this article, we will explore five different ways to run system commands in Ruby, providing examples and explanations for each method.

1. Using backticks

One of the simplest ways to run system commands in Ruby is by using backticks. This method allows you to execute a command and capture its output as a string.

result = `ls`
puts result

Explanation:

In this example, the `ls` command is executed, and the output is stored in the variable result. The result is then printed to the console.

2. Using system method

The system method in Ruby allows you to run system commands and display their output in real-time.

system("ls")

Explanation:

When the system method is called with the command "ls", it will display the output of the ls command directly to the console.

3. Using exec method

The exec method in Ruby replaces the current process with the specified system command.

exec("ls")
puts "This line will not be executed"

Explanation:

When the exec method is called with the command "ls", the current process is replaced by the ls command, and any subsequent code will not be executed.

4. Using popen method

The popen method in Ruby allows you to run system commands and interact with their input and output streams.

IO.popen("ls") do |io|
  puts io.read
end

Explanation:

In this example, the ls command is executed using the popen method, and the output is read from the input stream and printed to the console.

5. Using Open3 module

The Open3 module in Ruby provides a more advanced way to run system commands, allowing you to capture the output, error messages, and status of the command.

require 'open3'

stdout, stderr, status = Open3.capture3("ls")
puts stdout
puts stderr
puts status

Explanation:

In this example, the capture3 method from the Open3 module is used to run the ls command and capture its output, error messages, and status. The output, error messages, and status are then printed to the console.

Conclusion

Running system commands in Ruby can be a powerful tool for interacting with the underlying system. By using the methods outlined in this article, you can execute system commands, capture their output, and interact with their input and output streams in a variety of ways.