In the world of automation, Ansible has become one of the most popular tools for managing and deploying infrastructure. With its simple syntax and powerful capabilities, it allows users to automate a wide range of tasks across multiple machines with ease.

One of the key features that makes Ansible so versatile is its ability to execute commands on remote hosts using either shell or command modules. While both options achieve similar results, they have important differences that can make one more suitable than the other depending on the task at hand. In this article, we will take a closer look at the differences between Ansible Shell and Command modules, how they work, and when you should use each one.

In Ansible, both the shell and command modules are used to execute commands on remote hosts. However, they have some differences in how they handle command execution.

command module: This module is the default choice for executing commands in Ansible. It runs the command on the remote host directly, without any shell interpretation. It is suitable for running simple commands or when you don't need shell features like pipes, redirects, or variables.

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Here's an example of using the command module:

yaml

Copy code

- name: Run a command with the command module

  command: echo "Hello, world!"

shell module: The shell module is used when you need to run a command that requires shell features. It executes the command through the default shell on the remote host (usually /bin/sh or /bin/bash). This module allows you to use shell operators, pipes, redirects, and other shell-related features.

Here's an example of using the shell module:

yaml

Copy code

- name: Run a command with the shell module

  shell: echo "Hello, world!"

While the shell module provides more flexibility, it's generally recommended to use the command module whenever possible. Using the command module is safer because it bypasses the shell and reduces the risk of shell injection vulnerabilities.

Additionally, the command module is more efficient since it doesn't involve launching a shell process. The shell module incurs the overhead of starting a shell on the remote host, which can impact performance when executing a large number of commands.

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Conclusion:

In conclusion, the choice between Ansible Shell and Command depends on the specific use case. If you need to execute a single command or run a script, Command is the way to go. However, if you want to perform more complex tasks that require multiple commands, Shell is the better option. Additionally, using Shell allows for greater flexibility as it supports variables and loops. Ultimately, it's important to understand the strengths and limitations of each approach and choose accordingly. So next time you're faced with this decision in your Ansible playbook, consider your needs carefully before making a choice.

If you want to know more about ansible shell and command, visit this blog Ansible Shell vs Command !