How to set environment variables in Jenkins?

This can be done via EnvInject plugin in the following way:

1. Create an "Execute shell" build step that runs:

   echo AOEU=$(echo aoeu) > propsfile
   

2. Create an Inject environment variables build step and set "Properties File Path" to propsfile.

Note: This plugin is (mostly) not compatible with the Pipeline plugin.

The simplest way

You can use EnvInject plugin to injects environment variables at build startup. For example:

How you know it's working

In my case, I needed to add the JMETER_HOME environment variable to be available via my Ant build scripts across all projects on my Jenkins server (Linux), in a way that would not interfere with my local build environment (Windows and Mac) in the build.xml script. Setting the environment variable via Manage Jenkins - Configure System - Global properties was the easiest and least intrusive way to accomplish this. No plug-ins are necessary.

The environment variable is then available in Ant via:

<property environment="env" />
<property name="jmeter.home" value="${env.JMETER_HOME}" />

This can be verified to works by adding:

<echo message="JMeter Home: ${jmeter.home}"/>

Which produces:

JMeter Home: ~/.jmeter

In my case, I had configure environment variables using the following option and it worked-

Manage Jenkins -> Configure System -> Global Properties -> Environment Variables -> Add

You can try something like this

stages {
        stage('Build') {
            environment { 
                    AOEU= sh (returnStdout: true, script: 'echo aoeu').trim()
                }
            steps {
                sh 'env'
                sh 'echo $AOEU'
            }
        }
    }