How to Use Variables in Azure Pipeline: Simple Guide

In Azure Pipelines, you use variables to store values that can be reused throughout your pipeline. Define variables in the variables section or inline, then reference them using $(variableName) syntax in your pipeline steps.

Syntax

Variables in Azure Pipelines are defined under the variables section. You can assign a value to each variable. To use a variable, reference it with $(variableName) inside your pipeline steps.

Example parts:

• variables: Section where variables are declared.
• variableName: value Assigns a value to a variable.
• $(variableName) References the variable's value.

yaml

variables:
  myVar: 'Hello World'

steps:
- script: echo $(myVar)

Example

This example shows how to declare a variable and use it in a script step to print its value.

yaml

trigger:
- main

variables:
  greeting: 'Hello from Azure Pipelines'

pool:
  vmImage: 'ubuntu-latest'

steps:
- script: echo $(greeting)
  displayName: 'Print greeting variable'

Output

Hello from Azure Pipelines

Common Pitfalls

Common mistakes when using variables include:

• Using incorrect syntax like ${variableName} instead of $(variableName).
• Trying to use variables before they are defined.
• Not quoting variable values with spaces, which can cause errors.
• Confusing runtime variables with template parameters.

yaml

variables:
  message: 'Hello World'

steps:
- script: echo ${message}  # Wrong syntax, will not work
- script: echo $(message)  # Correct syntax

Quick Reference

Concept	Syntax	Description
Define variable	variables: varName: value	Declare variables at the top level.
Use variable	$(varName)	Reference variable in steps or scripts.
Variable with spaces	varName: 'value with spaces'	Quote values with spaces.
Override variable	variables: varName: newValue	Change variable value in different scopes.

Key Takeaways

Define variables in the variables section using key-value pairs.

Reference variables with $(variableName) syntax inside steps.

Always quote variable values that contain spaces.

Avoid using incorrect syntax like ${variableName}.

Variables help reuse values and make pipelines easier to maintain.