In Azure DevOps, variables are used to store and manage configuration settings, secrets, or any other data that your pipelines, releases, or other tasks might need during their execution. These variables can be defined at various scopes, such as pipeline, job, or stage level, and can be used to customize and parameterize your CI/CD processes.

Here’s an overview of how variables work in Azure DevOps:

1. Pipeline Variables: These are global variables that can be used across all stages and jobs within a pipeline. They are defined in the pipeline’s settings and can be accessed by any task in the pipeline. Pipeline variables can be set as secret variables to store sensitive information securely.

2. Job and Stage Level Variables: These variables are specific to a particular job or stage within a pipeline. They can be used to customize the behavior of individual jobs or stages. Job-level variables can also be set as secrets.

3. Environment Variables: You can also set environment variables in your pipeline jobs. These variables can be used by tasks within the job and can influence the environment in which tasks are executed.

To define and use variables in Azure DevOps:

1. Defining Variables:

   • In the Azure DevOps pipeline editor, you can define variables either in the pipeline settings or within specific jobs or stages.

   • Use the variables keyword to define variables. For example:

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     variables: myVariable: "Hello, Azure DevOps!"

   • To define a secret variable, you can mark it as secret:

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     variables: mySecret: $(superSecret) # Reference to a secret variable

2. Using Variables:

   • You can reference variables within your tasks using the $() syntax. For example:

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     steps: - script: echo $(myVariable)

3. Secret Variables:

   • Secret variables are encrypted and securely stored, making them suitable for sensitive data such as API keys or passwords.
   • Secret variables are not logged in the pipeline output.
   • Secret variables are referenced the same way as regular variables, but they are not exposed in the logs.

Remember that the exact syntax and capabilities might change based on updates to Azure DevOps. Always refer to the official documentation or interface for the latest information on working with variables in Azure DevOps pipelines.