29. What does CI/CD mean? What's the usage of it?

CI/CD (Continuous Integration/Continuous Deployment) is a set of practices and tools that automate the process of building, testing, and deploying applications. CI/CD helps deliver code to production quickly and reliably.

Advantages of CI/CD:

1. Faster deployment: Automating the deployment process allows for quicker and more frequent changes to be introduced to production.
2. Higher code quality: Automated tests detect errors early, improving code quality and reducing the risk of failures.
3. Early error detection: Errors are detected and fixed early in the software development lifecycle, reducing the cost of repairs.
4. Fewer manual tasks: Automation reduces the number of manual tasks, increasing team efficiency and allowing focus on more valuable tasks.
5. Consistency across environments: CI/CD ensures that all environments (development, testing, production) are consistent and compliant with requirements.

Example of using CI/CD with Jenkins:

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'npm install'
            }
        }
        stage('Test') {
            steps {
                sh 'npm test'
            }
        }
        stage('Deploy') {
            steps {
                sh 'npm run deploy'
            }
        }
    }
}

CI/CD is a crucial component of modern development processes, enabling faster and more reliable software delivery.